Method and device for receiving a-ppdu in wireless lan system

ABSTRACT

Proposed are a method and a device for receiving an A-PPDU in a wireless LAN system. Specifically, a reception STA receives an A-PPDU from a transmission STA and decodes the A-PPDU. The A-PPDU includes a first PPDU for a primary 80 MHz channel and a second PPDU for a secondary 80 MHz channel. The first PPDU includes a first L-STF, a first L-LTF, a first L-SIG, a first RL-SIG, HE-SIG-A, HE-SIG-B, and first data. The second PPDU includes a pre-padding field, a second L-STF, a second L-LTF, a second L-SIG, a second RL-SIG, U-SIG, EHT-SIG, and second data. The pre-padding field consists of a sequence having no cross-correlation with the first L-STF and the first L-LTF.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2021/018326, filed on Dec. 6, 2021,which claims the benefit of earlier filing date and right of priority toKorean Application Nos. 10-2020-0182303, filed on Dec. 23, 2020, and10-2020-0188122, filed on Dec. 30, 2020, the contents of which are allhereby incorporated by reference herein in their entireties.

TECHNICAL FIELD

The present specification relates to a technique for receiving an A-PPDUin a WLAN system, and more particularly, to a method and apparatus forconfiguring a structure of an A-PPDU capable of simultaneouslytransmitting a HE PPDU and an EHT PPDU.

BACKGROUND

A wireless local area network (WLAN) has been enhanced in various ways.For example, the IEEE 802.11ax standard has proposed an enhancedcommunication environment by using orthogonal frequency divisionmultiple access (OFDMA) and downlink multi-user multiple input multipleoutput (DL MU MIMO) schemes.

The present specification proposes a technical feature that can beutilized in a new communication standard. For example, the newcommunication standard may be an extreme high throughput (EHT) standardwhich is currently being discussed. The EHT standard may use anincreased bandwidth, an enhanced PHY layer protocol data unit (PPDU)structure, an enhanced sequence, a hybrid automatic repeat request(HARQ) scheme, or the like, which is newly proposed. The EHT standardmay be called the IEEE 802.11be standard.

An increased number of spatial streams may be used in the new wirelessLAN standard. In this case, in order to properly use the increasednumber of spatial streams, a signaling technique in the WLAN system mayneed to be improved.

SUMMARY

This specification proposes a method and apparatus for receiving anA-PPDU in a WLAN system.

An example of the present specification proposes a method for receivingan A-PPDU.

The present embodiment may be performed in a network environment inwhich a next-generation wireless LAN system (IEEE 802.11be or EHTwireless LAN system) is supported. The next-generation wireless LANsystem may be a wireless LAN system improved from the 802.11ax system,and may satisfy backward compatibility with the 802.11ax system.

This embodiment proposes a method for designing a structure of an A-PPDUin which HE PPDU and EHT PPDU are simultaneously transmitted. Inparticular, this embodiment proposes a method of solving the decodingproblem of the HE PPDU and the EHT PPDU by inserting a pre-padding fieldinto the EHT PPDU in the A-PPDU when SST is applied to the EHT STA.

A receiving station (STA) receives an Aggregated-Physical Protocol DataUnit (A-PPDU) from a transmitting STA.

The receiving STA decodes the A-PPDU.

The A-PPDU includes a first PPDU for a primary 80 MHz channel and asecond PPDU for a secondary 80 MHz channel. The first PPDU is a PPDUsupporting a High Efficiency (HE) WLAN system, and the second PPDU is aPPDU supporting an Extremely High Throughput (EHT) WLAN system. That is,the HE PPDU and the EHT PPDU may be aggregated with each other in thefrequency domain and transmitted simultaneously through the A-PPDU.Preferably, the HE PPDU is configured on the primary 80 MHz channel andthe EHT PPDU is configured on the secondary 80 MHz channel.

The first PPDU includes a first Legacy-Short Training Field (L-STF), afirst Legacy-Long Training Field (L-LTF), a first Legacy-Signal (L-SIG),and a first Repeated Legacy-Signal (RL-SIG), a High Efficiency-Signal-A(HE-SIG-A), a HE-SIG-B, a HE-STF, a HE-LTF, and a first data. The secondPPDU includes a pre-padding field, a second L-STF, a second L-LTF, asecond L-SIG, a second RL-SIG, a Universal-Signal (U-SIG), an ExtremelyHigh Throughput-Signal (EHT-SIG), and a second data.

The pre-padding field is configured of a sequence having nocross-correlation with the first L-STF and the first L-LTF. Also, thepre-padding field may be a field formed by repeating a field included inthe first or second PPDU once or several times.

According to the embodiment proposed in the present specification, byinserting a pre-padding field into the EHT PPDU in the A-PPDU that cansimultaneously transmit the HE PPDU and the EHT PPDU, the decodecombining problem for a 160 MHz capable HE STA is solved, and there isan effect of increasing the decoding efficiency of the HE STA and theEHT STA.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a transmitting apparatus and/or receivingapparatus of the present specification.

FIG. 2 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

FIG. 3 illustrates a general link setup process.

FIG. 4 illustrates an example of a PPDU used in an IEEE standard.

FIG. 5 illustrates a layout of resource units (RUs) used in a band of 20MHz.

FIG. 6 illustrates a layout of RUs used in a band of 40 MHz.

FIG. 7 illustrates a layout of RUs used in a band of 80 MHz.

FIG. 8 illustrates a structure of an HE-SIG-B field.

FIG. 9 illustrates an example in which a plurality of user STAs areallocated to the same RU through a MU-MIMO scheme.

FIG. 10 illustrates an example of a PPDU used in the presentspecification.

FIG. 11 illustrates an example of a modified transmission device and/orreceiving device of the present specification.

FIG. 12 is a diagram of a representative Aggregated PPDU.

FIG. 13 shows an example of the structure of U-SIG.

FIG. 14 shows an example of an A-PPDU in which each sub-PPDU isconfigured in units of 80 MHz.

FIG. 15 shows an example of an A-PPDU in which each sub-PPDU isconfigured in units of 80 MHz.

FIG. 16 shows an example of an A-PPDU in which each sub-PPDU isconfigured in units of 80 MHz.

FIG. 17 shows an example of an A-PPDU in which each sub-PPDU isconfigured in units of 80 MHz.

FIG. 18 is a flowchart illustrating the operation of the transmittingapparatus/device according to the present embodiment.

FIG. 19 is a flowchart illustrating the operation of the receivingapparatus/device according to the present embodiment.

FIG. 20 is a flowchart illustrating a procedure for transmitting anA-PPDU by a transmitting STA according to this embodiment.

FIG. 21 is a flowchart illustrating a procedure for receiving an A-PPDUby a receiving STA according to this embodiment.

DETAILED DESCRIPTION

In the present specification, “A or B” may mean “only A”, “only B” or“both A and B”. In other words, in the present specification, “A or B”may be interpreted as “A and/or B”. For example, in the presentspecification, “A, B, or C” may mean “only A”, “only B”, “only C”, or“any combination of A, B, C”.

A slash (/) or comma used in the present specification may mean“and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B”may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C”may mean “A, B, or C”.

In the present specification, “at least one of A and B” may mean “onlyA”, “only B”, or “both A and B”. In addition, in the presentspecification, the expression “at least one of A or B” or “at least oneof A and/or B” may be interpreted as “at least one of A and B”.

In addition, in the present specification, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present specification may mean“for example”. Specifically, when indicated as “control information(EHT-signal)”, it may denote that “EHT-signal” is proposed as an exampleof the “control information”. In other words, the “control information”of the present specification is not limited to “EHT-signal”, and“EHT-signal” may be proposed as an example of the “control information”.In addition, when indicated as “control information (i.e., EHT-signal)”,it may also mean that “EHT-signal” is proposed as an example of the“control information”.

Technical features described individually in one figure in the presentspecification may be individually implemented, or may be simultaneouslyimplemented.

The following example of the present specification may be applied tovarious wireless communication systems. For example, the followingexample of the present specification may be applied to a wireless localarea network (WLAN) system. For example, the present specification maybe applied to the IEEE 802.11a/g/n/ac standard or the IEEE 802.11axstandard. In addition, the present specification may also be applied tothe newly proposed EHT standard or IEEE 802.11be standard. In addition,the example of the present specification may also be applied to a newWLAN standard enhanced from the EHT standard or the IEEE 802.11bestandard. In addition, the example of the present specification may beapplied to a mobile communication system. For example, it may be appliedto a mobile communication system based on long term evolution (LTE)depending on a 3rd generation partnership project (3GPP) standard andbased on evolution of the LTE. In addition, the example of the presentspecification may be applied to a communication system of a 5G NRstandard based on the 3GPP standard.

Hereinafter, in order to describe a technical feature of the presentspecification, a technical feature applicable to the presentspecification will be described.

FIG. 1 shows an example of a transmitting apparatus and/or receivingapparatus of the present specification.

In the example of FIG. 1 , various technical features described belowmay be performed. FIG. 1 relates to at least one station (STA). Forexample, STAs 110 and 120 of the present specification may also becalled in various terms such as a mobile terminal, a wireless device, awireless transmit/receive unit (WTRU), a user equipment (UE), a mobilestation (MS), a mobile subscriber unit, or simply a user. The STAs 110and 120 of the present specification may also be called in various termssuch as a network, a base station, a node-B, an access point (AP), arepeater, a router, a relay, or the like. The STAs 110 and 120 of thepresent specification may also be referred to as various names such as areceiving apparatus, a transmitting apparatus, a receiving STA, atransmitting STA, a receiving device, a transmitting device, or thelike.

For example, the STAs 110 and 120 may serve as an AP or a non-AP. Thatis, the STAs 110 and 120 of the present specification may serve as theAP and/or the non-AP.

The STAs 110 and 120 of the present specification may support variouscommunication standards together in addition to the IEEE 802.11standard. For example, a communication standard (e.g., LTE, LTE-A, 5G NRstandard) or the like based on the 3GPP standard may be supported. Inaddition, the STA of the present specification may be implemented asvarious devices such as a mobile phone, a vehicle, a personal computer,or the like. In addition, the STA of the present specification maysupport communication for various communication services such as voicecalls, video calls, data communication, and self-driving(autonomous-driving), or the like.

The STAs 110 and 120 of the present specification may include a mediumaccess control (MAC) conforming to the IEEE 802.11 standard and aphysical layer interface for a radio medium.

The STAs 110 and 120 will be described below with reference to asub-figure (a) of FIG. 1 .

The first STA 110 may include a processor 111, a memory 112, and atransceiver 113. The illustrated process, memory, and transceiver may beimplemented individually as separate chips, or at least twoblocks/functions may be implemented through a single chip.

The transceiver 113 of the first STA performs a signaltransmission/reception operation. Specifically, an IEEE 802.11 packet(e.g., IEEE 802.11a/b/g/n/ac/ax/be, etc.) may be transmitted/received.

For example, the first STA 110 may perform an operation intended by anAP. For example, the processor 111 of the AP may receive a signalthrough the transceiver 113, process a reception (RX) signal, generate atransmission (TX) signal, and provide control for signal transmission.The memory 112 of the AP may store a signal (e.g., RX signal) receivedthrough the transceiver 113, and may store a signal (e.g., TX signal) tobe transmitted through the transceiver.

For example, the second STA 120 may perform an operation intended by anon-AP STA. For example, a transceiver 123 of a non-AP performs a signaltransmission/reception operation. Specifically, an IEEE 802.11 packet(e.g., IEEE 802.11a/b/g/n/ac/ax/be packet, etc.) may betransmitted/received.

For example, a processor 121 of the non-AP STA may receive a signalthrough the transceiver 123, process an RX signal, generate a TX signal,and provide control for signal transmission. A memory 122 of the non-APSTA may store a signal (e.g., RX signal) received through thetransceiver 123, and may store a signal (e.g., TX signal) to betransmitted through the transceiver.

For example, an operation of a device indicated as an AP in thespecification described below may be performed in the first STA 110 orthe second STA 120. For example, if the first STA 110 is the AP, theoperation of the device indicated as the AP may be controlled by theprocessor 111 of the first STA 110, and a related signal may betransmitted or received through the transceiver 113 controlled by theprocessor 111 of the first STA 110. In addition, control informationrelated to the operation of the AP or a TX/RX signal of the AP may bestored in the memory 112 of the first STA 110. In addition, if thesecond STA 120 is the AP, the operation of the device indicated as theAP may be controlled by the processor 121 of the second STA 120, and arelated signal may be transmitted or received through the transceiver123 controlled by the processor 121 of the second STA 120. In addition,control information related to the operation of the AP or a TX/RX signalof the AP may be stored in the memory 122 of the second STA 120.

For example, in the specification described below, an operation of adevice indicated as a non-AP (or user-STA) may be performed in the firstSTA 110 or the second STA 120. For example, if the second STA 120 is thenon-AP, the operation of the device indicated as the non-AP may becontrolled by the processor 121 of the second STA 120, and a relatedsignal may be transmitted or received through the transceiver 123controlled by the processor 121 of the second STA 120. In addition,control information related to the operation of the non-AP or a TX/RXsignal of the non-AP may be stored in the memory 122 of the second STA120. For example, if the first STA 110 is the non-AP, the operation ofthe device indicated as the non-AP may be controlled by the processor111 of the first STA 110, and a related signal may be transmitted orreceived through the transceiver 113 controlled by the processor 111 ofthe first STA 110. In addition, control information related to theoperation of the non-AP or a TX/RX signal of the non-AP may be stored inthe memory 112 of the first STA 110.

In the specification described below, a device called a(transmitting/receiving) STA, a first STA, a second STA, a STA1, a STA2,an AP, a first AP, a second AP, an AP1, an AP2, a(transmitting/receiving) terminal, a (transmitting/receiving) device, a(transmitting/receiving) apparatus, a network, or the like may imply theSTAs 110 and 120 of FIG. 1 . For example, a device indicated as, withouta specific reference numeral, the (transmitting/receiving) STA, thefirst STA, the second STA, the STA1, the STA2, the AP, the first AP, thesecond AP, the AP′, the AP2, the (transmitting/receiving) terminal, the(transmitting/receiving) device, the (transmitting/receiving) apparatus,the network, or the like may imply the STAs 110 and 120 of FIG. 1 . Forexample, in the following example, an operation in which various STAstransmit/receive a signal (e.g., a PPDU) may be performed in thetransceivers 113 and 123 of FIG. 1 . In addition, in the followingexample, an operation in which various STAs generate a TX/RX signal orperform data processing and computation in advance for the TX/RX signalmay be performed in the processors 111 and 121 of FIG. 1 . For example,an example of an operation for generating the TX/RX signal or performingthe data processing and computation in advance may include: 1) anoperation ofdetermining/obtaining/configuring/computing/decoding/encoding bitinformation of a sub-field (SIG, STF, LTF, Data) included in a PPDU; 2)an operation of determining/configuring/obtaining a time resource orfrequency resource (e.g., a subcarrier resource) or the like used forthe sub-field (SIG, STF, LTF, Data) included the PPDU; 3) an operationof determining/configuring/obtaining a specific sequence (e.g., a pilotsequence, an STF/LTF sequence, an extra sequence applied to SIG) or thelike used for the sub-field (SIG, STF, LTF, Data) field included in thePPDU; 4) a power control operation and/or power saving operation appliedfor the STA; and 5) an operation related todetermining/obtaining/configuring/decoding/encoding or the like of anACK signal. In addition, in the following example, a variety ofinformation used by various STAs fordetermining/obtaining/configuring/computing/decoding/decoding a TX/RXsignal (e.g., information related to a field/subfield/controlfield/parameter/power or the like) may be stored in the memories 112 and122 of FIG. 1 .

The aforementioned device/STA of the sub-figure (a) of FIG. 1 may bemodified as shown in the sub-figure (b) of FIG. 1 . Hereinafter, theSTAs 110 and 120 of the present specification will be described based onthe sub-figure (b) of FIG. 1 .

For example, the transceivers 113 and 123 illustrated in the sub-figure(b) of FIG. 1 may perform the same function as the aforementionedtransceiver illustrated in the sub-figure (a) of FIG. 1 . For example,processing chips 114 and 124 illustrated in the sub-figure (b) of FIG. 1may include the processors 111 and 121 and the memories 112 and 122. Theprocessors 111 and 121 and memories 112 and 122 illustrated in thesub-figure (b) of FIG. 1 may perform the same function as theaforementioned processors 111 and 121 and memories 112 and 122illustrated in the sub-figure (a) of FIG. 1 .

A mobile terminal, a wireless device, a wireless transmit/receive unit(WTRU), a user equipment (UE), a mobile station (MS), a mobilesubscriber unit, a user, a user STA, a network, a base station, aNode-B, an access point (AP), a repeater, a router, a relay, a receivingunit, a transmitting unit, a receiving STA, a transmitting STA, areceiving device, a transmitting device, a receiving apparatus, and/or atransmitting apparatus, which are described below, may imply the STAs110 and 120 illustrated in the sub-figure (a)/(b) of FIG. 1 , or mayimply the processing chips 114 and 124 illustrated in the sub-figure (b)of FIG. 1 . That is, a technical feature of the present specificationmay be performed in the STAs 110 and 120 illustrated in the sub-figure(a)/(b) of FIG. 1 , or may be performed only in the processing chips 114and 124 illustrated in the sub-figure (b) of FIG. 1 . For example, atechnical feature in which the transmitting STA transmits a controlsignal may be understood as a technical feature in which a controlsignal generated in the processors 111 and 121 illustrated in thesub-figure (a)/(b) of FIG. 1 is transmitted through the transceivers 113and 123 illustrated in the sub-figure (a)/(b) of FIG. 1 . Alternatively,the technical feature in which the transmitting STA transmits thecontrol signal may be understood as a technical feature in which thecontrol signal to be transferred to the transceivers 113 and 123 isgenerated in the processing chips 114 and 124 illustrated in thesub-figure (b) of FIG. 1 .

For example, a technical feature in which the receiving STA receives thecontrol signal may be understood as a technical feature in which thecontrol signal is received by means of the transceivers 113 and 123illustrated in the sub-figure (a) of FIG. 1 . Alternatively, thetechnical feature in which the receiving STA receives the control signalmay be understood as the technical feature in which the control signalreceived in the transceivers 113 and 123 illustrated in the sub-figure(a) of FIG. 1 is obtained by the processors 111 and 121 illustrated inthe sub-figure (a) of FIG. 1 . Alternatively, the technical feature inwhich the receiving STA receives the control signal may be understood asthe technical feature in which the control signal received in thetransceivers 113 and 123 illustrated in the sub-figure (b) of FIG. 1 isobtained by the processing chips 114 and 124 illustrated in thesub-figure (b) of FIG. 1 .

Referring to the sub-figure (b) of FIG. 1 , software codes 115 and 125may be included in the memories 112 and 122. The software codes 115 and126 may include instructions for controlling an operation of theprocessors 111 and 121. The software codes 115 and 125 may be includedas various programming languages.

The processors 111 and 121 or processing chips 114 and 124 of FIG. 1 mayinclude an application-specific integrated circuit (ASIC), otherchipsets, a logic circuit and/or a data processing device. The processormay be an application processor (AP). For example, the processors 111and 121 or processing chips 114 and 124 of FIG. 1 may include at leastone of a digital signal processor (DSP), a central processing unit(CPU), a graphics processing unit (GPU), and a modulator and demodulator(modem). For example, the processors 111 and 121 or processing chips 114and 124 of FIG. 1 may be SNAPDRAGON™ series of processors made byQualcomm®, EXYNOS™ series of processors made by Samsung®, A series ofprocessors made by Apple®, HELIO™ series of processors made byMediaTek®, ATOM™ series of processors made by Intel® or processorsenhanced from these processors.

In the present specification, an uplink may imply a link forcommunication from a non-AP STA to an SP STA, and an uplinkPPDU/packet/signal or the like may be transmitted through the uplink. Inaddition, in the present specification, a downlink may imply a link forcommunication from the AP STA to the non-AP STA, and a downlinkPPDU/packet/signal or the like may be transmitted through the downlink.

FIG. 2 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

An upper part of FIG. 2 illustrates the structure of an infrastructurebasic service set (BSS) of institute of electrical and electronicengineers (IEEE) 802.11.

Referring the upper part of FIG. 2 , the wireless LAN system may includeone or more infrastructure BSSs 200 and 205 (hereinafter, referred to asBSS). The BSSs 200 and 205 as a set of an AP and a STA such as an accesspoint (AP) 225 and a station (STA1) 200-1 which are successfullysynchronized to communicate with each other are not concepts indicatinga specific region. The BSS 205 may include one or more STAs 205-1 and205-2 which may be joined to one AP 230.

The BSS may include at least one STA, APs providing a distributionservice, and a distribution system (DS) 210 connecting multiple APs.

The distribution system 210 may implement an extended service set (ESS)240 extended by connecting the multiple BSSs 200 and 205. The ESS 240may be used as a term indicating one network configured by connectingone or more APs 225 or 230 through the distribution system 210. The APincluded in one ESS 240 may have the same service set identification (SSID).

A portal 220 may serve as a bridge which connects the wireless LANnetwork (IEEE 802.11) and another network (e.g., 802.X).

In the BSS illustrated in the upper part of FIG. 2 , a network betweenthe APs 225 and 230 and a network between the APs 225 and 230 and theSTAs 200-1, 205-1, and 205-2 may be implemented. However, the network isconfigured even between the STAs without the APs 225 and 230 to performcommunication. A network in which the communication is performed byconfiguring the network even between the STAs without the APs 225 and230 is defined as an Ad-Hoc network or an independent basic service set(IBSS).

A lower part of FIG. 2 illustrates a conceptual view illustrating theIBSS.

Referring to the lower part of FIG. 2 , the IBSS is a BSS that operatesin an Ad-Hoc mode. Since the IBSS does not include the access point(AP), a centralized management entity that performs a managementfunction at the center does not exist. That is, in the IBSS, STAs 250-1,250-2, 250-3, 255-4, and 255-5 are managed by a distributed manner. Inthe IBSS, all STAs 250-1, 250-2, 250-3, 255-4, and 255-5 may beconstituted by movable STAs and are not permitted to access the DS toconstitute a self-contained network.

FIG. 3 illustrates a general link setup process.

In S310, a STA may perform a network discovery operation. The networkdiscovery operation may include a scanning operation of the STA. Thatis, to access a network, the STA needs to discover a participatingnetwork. The STA needs to identify a compatible network beforeparticipating in a wireless network, and a process of identifying anetwork present in a particular area is referred to as scanning.Scanning methods include active scanning and passive scanning.

FIG. 3 illustrates a network discovery operation including an activescanning process. In active scanning, a STA performing scanningtransmits a probe request frame and waits for a response to the proberequest frame in order to identify which AP is present around whilemoving to channels. A responder transmits a probe response frame as aresponse to the probe request frame to the STA having transmitted theprobe request frame. Here, the responder may be a STA that transmits thelast beacon frame in a BSS of a channel being scanned. In the BSS, sincean AP transmits a beacon frame, the AP is the responder. In an IBSS,since STAs in the IBSS transmit a beacon frame in turns, the responderis not fixed. For example, when the STA transmits a probe request framevia channel 1 and receives a probe response frame via channel 1, the STAmay store BSS-related information included in the received proberesponse frame, may move to the next channel (e.g., channel 2), and mayperform scanning (e.g., transmits a probe request and receives a proberesponse via channel 2) by the same method.

Although not shown in FIG. 3 , scanning may be performed by a passivescanning method. In passive scanning, a STA performing scanning may waitfor a beacon frame while moving to channels. A beacon frame is one ofmanagement frames in IEEE 802.11 and is periodically transmitted toindicate the presence of a wireless network and to enable the STAperforming scanning to find the wireless network and to participate inthe wireless network. In a BSS, an AP serves to periodically transmit abeacon frame. In an IBSS, STAs in the IBSS transmit a beacon frame inturns. Upon receiving the beacon frame, the STA performing scanningstores information related to a BSS included in the beacon frame andrecords beacon frame information in each channel while moving to anotherchannel. The STA having received the beacon frame may store BSS-relatedinformation included in the received beacon frame, may move to the nextchannel, and may perform scanning in the next channel by the samemethod.

After discovering the network, the STA may perform an authenticationprocess in S320. The authentication process may be referred to as afirst authentication process to be clearly distinguished from thefollowing security setup operation in S340. The authentication processin S320 may include a process in which the STA transmits anauthentication request frame to the AP and the AP transmits anauthentication response frame to the STA in response. The authenticationframes used for an authentication request/response are managementframes.

The authentication frames may include information related to anauthentication algorithm number, an authentication transaction sequencenumber, a status code, a challenge text, a robust security network(RSN), and a finite cyclic group.

The STA may transmit the authentication request frame to the AP. The APmay determine whether to allow the authentication of the STA based onthe information included in the received authentication request frame.The AP may provide the authentication processing result to the STA viathe authentication response frame.

When the STA is successfully authenticated, the STA may perform anassociation process in S330. The association process includes a processin which the STA transmits an association request frame to the AP andthe AP transmits an association response frame to the STA in response.The association request frame may include, for example, informationrelated to various capabilities, a beacon listen interval, a service setidentifier (SSID), a supported rate, a supported channel, RSN, amobility domain, a supported operating class, a traffic indication map(TIM) broadcast request, and an interworking service capability. Theassociation response frame may include, for example, information relatedto various capabilities, a status code, an association ID (AID), asupported rate, an enhanced distributed channel access (EDCA) parameterset, a received channel power indicator (RCPI), a receivedsignal-to-noise indicator (RSNI), a mobility domain, a timeout interval(association comeback time), an overlapping BSS scanning parameter, aTIM broadcast response, and a QoS map.

In S340, the STA may perform a security setup process. The securitysetup process in S340 may include a process of setting up a private keythrough four-way handshaking, for example, through an extensibleauthentication protocol over LAN (EAPOL) frame.

FIG. 4 illustrates an example of a PPDU used in an IEEE standard.

As illustrated, various types of PHY protocol data units (PPDUs) areused in IEEE a/g/n/ac standards. Specifically, an LTF and a STF includea training signal, a SIG-A and a SIG-B include control information for areceiving STA, and a data field includes user data corresponding to aPSDU (MAC PDU/aggregated MAC PDU).

FIG. 4 also includes an example of an HE PPDU according to IEEE802.11ax. The HE PPDU according to FIG. 4 is an illustrative PPDU formultiple users. An HE-SIG-B may be included only in a PPDU for multipleusers, and an HE-SIG-B may be omitted in a PPDU for a single user.

As illustrated in FIG. 4 , the HE-PPDU for multiple users (MUs) mayinclude a legacy-short training field (L-STF), a legacy-long trainingfield (L-LTF), a legacy-signal (L-SIG), a high efficiency-signal A(HE-SIG A), a high efficiency-signal-B (HE-SIG B), a highefficiency-short training field (HE-STF), a high efficiency-longtraining field (HE-LTF), a data field (alternatively, an MAC payload),and a packet extension (PE) field. The respective fields may betransmitted for illustrated time periods (i.e., 4 or 8 μs).

Hereinafter, a resource unit (RU) used for a PPDU is described. An RUmay include a plurality of subcarriers (or tones). An RU may be used totransmit a signal to a plurality of STAs according to OFDMA. Further, anRU may also be defined to transmit a signal to one STA. An RU may beused for an STF, an LTF, a data field, or the like.

FIG. 5 illustrates a layout of resource units (RUs) used in a band of 20MHz.

As illustrated in FIG. 5 , resource units (RUs) corresponding todifferent numbers of tones (i.e., subcarriers) may be used to form somefields of an HE-PPDU. For example, resources may be allocated inillustrated RUs for an HE-STF, an HE-LTF, and a data field.

As illustrated in the uppermost part of FIG. 5 , a 26-unit (i.e., a unitcorresponding to 26 tones) may be disposed. Six tones may be used for aguard band in the leftmost band of the MHz band, and five tones may beused for a guard band in the rightmost band of the 20 MHz band. Further,seven DC tones may be inserted in a center band, that is, a DC band, anda 26-unit corresponding to 13 tones on each of the left and right sidesof the DC band may be disposed. A 26-unit, a 52-unit, and a 106-unit maybe allocated to other bands. Each unit may be allocated for a receivingSTA, that is, a user.

The layout of the RUs in FIG. 5 may be used not only for a multipleusers (MUs) but also for a single user (SU), in which case one 242-unitmay be used and three DC tones may be inserted as illustrated in thelowermost part of FIG. 5 .

Although FIG. 5 proposes RUs having various sizes, that is, a 26-RU, a52-RU, a 106-RU, and a 242-RU, specific sizes of RUs may be extended orincreased. Therefore, the present embodiment is not limited to thespecific size of each RU (i.e., the number of corresponding tones).

FIG. 6 illustrates a layout of RUs used in a band of 40 MHz.

Similarly to FIG. 5 in which RUs having various sizes are used, a 26-RU,a 52-RU, a 106-RU, a 242-RU, a 484-RU, and the like may be used in anexample of FIG. 6 . Further, five DC tones may be inserted in a centerfrequency, 12 tones may be used for a guard band in the leftmost band ofthe 40 MHz band, and 11 tones may be used for a guard band in therightmost band of the 40 MHz band.

As illustrated in FIG. 6 , when the layout of the RUs is used for asingle user, a 484-RU may be used. The specific number of RUs may bechanged similarly to FIG. 5 .

FIG. 7 illustrates a layout of RUs used in a band of 80 MHz.

Similarly to FIG. 5 and FIG. 6 in which RUs having various sizes areused, a 26-RU, a 52-RU, a 106-RU, a 242-RU, a 484-RU, a 996-RU, and thelike may be used in an example of FIG. 7 . Further, seven DC tones maybe inserted in the center frequency, 12 tones may be used for a guardband in the leftmost band of the 80 MHz band, and 11 tones may be usedfor a guard band in the rightmost band of the 80 MHz band. In addition,a 26-RU corresponding to 13 tones on each of the left and right sides ofthe DC band may be used.

As illustrated in FIG. 7 , when the layout of the RUs is used for asingle user, a 996-RU may be used, in which case five DC tones may beinserted.

The RU described in the present specification may be used in uplink (UL)communication and downlink (DL) communication. For example, when UL-MUcommunication which is solicited by a trigger frame is performed, atransmitting STA (e.g., an AP) may allocate a first RU (e.g.,26/52/106/242-RU, etc.) to a first STA through the trigger frame, andmay allocate a second RU (e.g., 26/52/106/242-RU, etc.) to a second STA.Thereafter, the first STA may transmit a first trigger-based PPDU basedon the first RU, and the second STA may transmit a second trigger-basedPPDU based on the second RU. The first/second trigger-based PPDU istransmitted to the AP at the same (or overlapped) time period.

For example, when a DL MU PPDU is configured, the transmitting STA(e.g., AP) may allocate the first RU (e.g., 26/52/106/242-RU. etc.) tothe first STA, and may allocate the second RU (e.g., 26/52/106/242-RU,etc.) to the second STA. That is, the transmitting STA (e.g., AP) maytransmit HE-STF, HE-LTF, and Data fields for the first STA through thefirst RU in one MU PPDU, and may transmit HE-STF, HE-LTF, and Datafields for the second STA through the second RU.

Information related to a layout of the RU may be signaled throughHE-SIG-B.

FIG. 8 illustrates a structure of an HE-SIG-B field.

As illustrated, an HE-SIG-B field 810 includes a common field 820 and auser-specific field 830. The common field 820 may include informationcommonly applied to all users (i.e., user STAs) which receive SIG-B. Theuser-specific field 830 may be called a user-specific control field.When the SIG-B is transferred to a plurality of users, the user-specificfield 830 may be applied only any one of the plurality of users.

As illustrated in FIG. 8 , the common field 820 and the user-specificfield 830 may be separately encoded.

The common field 820 may include RU allocation information of N*8 bits.For example, the RU allocation information may include informationrelated to a location of an RU. For example, when a 20 MHz channel isused as shown in FIG. 5 , the RU allocation information may includeinformation related to a specific frequency band to which a specific RU(26-RU/52-RU/106-RU) is arranged.

An example of a case in which the RU allocation information consists of8 bits is as follows.

TABLE 1 RU Allocation subfield (B7 B6 B5 B4 Number B3 B2 B1 B0) #1 #2 #3#4 #5 #6 #7 #8 #9 of entries 00000000 26 26 26 26 26 26 26 26 26 100000001 26 26 26 26 26 26 26 52 1 00000010 26 26 26 26 26 52 26 26 100000011 26 26 26 26 26 52 52 1 00000100 26 26 52 26 26 26 26 26 100000101 26 26 52 26 26 26 52 1 00000110 26 26 52 26 52 26 26 1 0000011126 26 52 26 52 52 1 00001000 52 26 26 26 26 26 26 26 1 00001001 52 26 2626 26 26 52 1 00001010 52 26 26 26 52 26 26 1

As shown the example of FIG. 5 , up to nine 26-RUs may be allocated tothe 20 MHz channel. When the RU allocation information of the commonfield 820 is set to “00000000” as shown in Table 1, the nine 26-RUs maybe allocated to a corresponding channel (i.e., 20 MHz). In addition,when the RU allocation information of the common field 820 is set to“00000001” as shown in Table 1, seven 26-RUs and one 52-RU are arrangedin a corresponding channel. That is, in the example of FIG. 5 , the52-RU may be allocated to the rightmost side, and the seven 26-RUs maybe allocated to the left thereof.

The example of Table 1 shows only some of RU locations capable ofdisplaying the RU allocation information.

For example, the RU allocation information may include an example ofTable 2 below.

TABLE 2 8 bits indices (B7 B6 B5 B4 Number B3 B2 B1 B0) #1 #2 #3 #4 #5#6 #7 #8 #9 of entries 01000y₂y₁y₀ 106 26 26 26 26 26 8 01001y₂y₁y₀ 10626 26 26 52 8

“01000y2y 1y0” relates to an example in which a 106-RU is allocated tothe leftmost side of the 20 MHz channel, and five 26-RUs are allocatedto the right side thereof. In this case, a plurality of STAs (e.g.,user-STAs) may be allocated to the 106-RU, based on a MU-MIMO scheme.Specifically, up to 8 STAs (e.g., user-STAs) may be allocated to the106-RU, and the number of STAs (e.g., user-STAs) allocated to the 106-RUis determined based on 3-bit information (y2y1y0). For example, when the3-bit information (y2y1y0) is set to N, the number of STAs (e.g.,user-STAs) allocated to the 106-RU based on the MU-MIMO scheme may beN+1.

In general, a plurality of STAs (e.g., user STAs) different from eachother may be allocated to a plurality of RUs. However, the plurality ofSTAs (e.g., user STAs) may be allocated to one or more RUs having atleast a specific size (e.g., 106 subcarriers), based on the MU-MIMOscheme.

As shown in FIG. 8 , the user-specific field 830 may include a pluralityof user fields. As described above, the number of STAs (e.g., user STAs)allocated to a specific channel may be determined based on the RUallocation information of the common field 820. For example, when the RUallocation information of the common field 820 is “00000000”, one userSTA may be allocated to each of nine 26-RUs (e.g., nine user STAs may beallocated). That is, up to 9 user STAs may be allocated to a specificchannel through an OFDMA scheme. In other words, up to 9 user STAs maybe allocated to a specific channel through a non-MU-MIMO scheme.

For example, when RU allocation is set to “01000y2y1y0”, a plurality ofSTAs may be allocated to the 106-RU arranged at the leftmost sidethrough the MU-MIMO scheme, and five user STAs may be allocated to five26-RUs arranged to the right side thereof through the non-MU MIMOscheme. This case is specified through an example of FIG. 9 .

FIG. 9 illustrates an example in which a plurality of user STAs areallocated to the same RU through a MU-MIMO scheme.

For example, when RU allocation is set to “01000010” as shown in FIG. 9, a 106-RU may be allocated to the leftmost side of a specific channel,and five 26-RUs may be allocated to the right side thereof. In addition,three user STAs may be allocated to the 106-RU through the MU-MIMOscheme. As a result, since eight user STAs are allocated, theuser-specific field 830 of HE-SIG-B may include eight user fields.

The eight user fields may be expressed in the order shown in FIG. 9 . Inaddition, as shown in FIG. 8 , two user fields may be implemented withone user block field.

The user fields shown in FIG. 8 and FIG. 9 may be configured based ontwo formats. That is, a user field related to a MU-MIMO scheme may beconfigured in a first format, and a user field related to a non-MIMOscheme may be configured in a second format. Referring to the example ofFIG. 9 , a user field 1 to a user field 3 may be based on the firstformat, and a user field 4 to a user field 8 may be based on the secondformat. The first format or the second format may include bitinformation of the same length (e.g., 21 bits).

Each user field may have the same size (e.g., 21 bits). For example, theuser field of the first format (the first of the MU-MIMO scheme) may beconfigured as follows.

For example, a first bit (i.e., B0-B10) in the user field (i.e., 21bits) may include identification information (e.g., STA-ID, partial AID,etc.) of a user STA to which a corresponding user field is allocated. Inaddition, a second bit (i.e., B11-B14) in the user field (i.e., 21 bits)may include information related to a spatial configuration.Specifically, an example of the second bit (i.e., B11-B14) may be asshown in Table 3 and Table 4 below.

TABLE 3 N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS)Total Number N_(user) B3 . . . B0 [1] [2] [3] [4] [5] [6] [7] [8]N_(STS) of entries 2 0000-0011 1-4 1 2-5 10 0100-0110 2-4 2 4-60111-1000 3-4 3 6-7 1001 4 4 8 3 0000-0011 1-4 1 1 3-6 13 0100-0110 2-42 1 5-7 0111-1000 3-4 3 1 7-8 1001-1011 2-4 2 2 6-8 1100 3 3 2 8 40000-0011 1-4 1 1 1 4-7 11 0100-0110 2-4 2 1 1 6-8 0111 3 3 1 1 81000-1001 2-3 2 2 1 7-8 1010 2 2 2 2 8

TABLE 4 N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS) N_(STS)Total Number N_(user) B3 . . . B0 [1] [2] [3] [4] [5] [6] [7] [8]N_(STS) of entries 5 0000-0011 1-4 1 1 1 1 5-8 7 0100-0101 2-3 2 1 1 17-8 0110 2 2 2 1 1 8 6 0000-0010 1-3 1 1 1 1 1 6-8 4 0011 2 2 1 1 1 1 87 0000-0001 1-2 1 1 1 1 1 1 7-8 2 8 0000 1 1 1 1 1 1 1 1 8 1

As shown in Table 3 and/or Table 4, the second bit (e.g., B11-B14) mayinclude information related to the number of spatial streams allocatedto the plurality of user STAs which are allocated based on the MU-MIMOscheme. For example, when three user STAs are allocated to the 106-RUbased on the MU-MIMO scheme as shown in FIG. 9 , N user is set to “3”.Therefore, values of N_STS[1], N_STS[2], and N_STS[3] may be determinedas shown in Table 3. For example, when a value of the second bit(B11-B14) is “0011”, it may be set to N_STS[1]=4, N_STS[2]=1,N_STS[3]=1. That is, in the example of FIG. 9 , four spatial streams maybe allocated to the user field 1, one spatial stream may be allocated tothe user field 1, and one spatial stream may be allocated to the userfield 3.

As shown in the example of Table 3 and/or Table 4, information (i.e.,the second bit, B11-B14) related to the number of spatial streams forthe user STA may consist of 4 bits. In addition, the information (i.e.,the second bit, B11-B14) on the number of spatial streams for the userSTA may support up to eight spatial streams. In addition, theinformation (i.e., the second bit, B11-B14) on the number of spatialstreams for the user STA may support up to four spatial streams for oneuser STA.

In addition, a third bit (i.e., B15-18) in the user field (i.e., 21bits) may include modulation and coding scheme (MCS) information. TheMCS information may be applied to a data field in a PPDU includingcorresponding SIG-B.

An MCS, MCS information, an MCS index, an MCS field, or the like used inthe present specification may be indicated by an index value. Forexample, the MCS information may be indicated by an index 0 to an index11. The MCS information may include information related to aconstellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM,256-QAM, 1024-QAM, etc.) and information related to a coding rate (e.g.,1/2, 2/3, 3/4, 5/6e, etc.). Information related to a channel coding type(e.g., LCC or LDPC) may be excluded in the MCS information.

In addition, a fourth bit (i.e., B19) in the user field (i.e., 21 bits)may be a reserved field.

In addition, a fifth bit (i.e., B20) in the user field (i.e., 21 bits)may include information related to a coding type (e.g., BCC or LDPC).That is, the fifth bit (i.e., B20) may include information related to atype (e.g., BCC or LDPC) of channel coding applied to the data field inthe PPDU including the corresponding SIG-B.

The aforementioned example relates to the user field of the first format(the format of the MU-MIMO scheme). An example of the user field of thesecond format (the format of the non-MU-MIMO scheme) is as follows.

A first bit (e.g., B0-B10) in the user field of the second format mayinclude identification information of a user STA. In addition, a secondbit (e.g., B11-B13) in the user field of the second format may includeinformation related to the number of spatial streams applied to acorresponding RU. In addition, a third bit (e.g., B14) in the user fieldof the second format may include information related to whether abeamforming steering matrix is applied. A fourth bit (e.g., B15-B18) inthe user field of the second format may include modulation and codingscheme (MCS) information. In addition, a fifth bit (e.g., B19) in theuser field of the second format may include information related towhether dual carrier modulation (DCM) is applied. In addition, a sixthbit (i.e., B20) in the user field of the second format may includeinformation related to a coding type (e.g., BCC or LDPC).

Hereinafter, a PPDU transmitted/received in a STA of the presentspecification will be described.

FIG. 10 illustrates an example of a PPDU used in the presentspecification.

The PPDU of FIG. 10 may be called in various terms such as an EHT PPDU,a TX PPDU, an RX PPDU, a first type or N-th type PPDU, or the like. Forexample, in the present specification, the PPDU or the EHT PPDU may becalled in various terms such as a TX PPDU, a RX PPDU, a first type orN-th type PPDU, or the like. In addition, the EHT PPDU may be used in anEHT system and/or a new WLAN system enhanced from the EHT system.

The PPDU of FIG. 10 may indicate the entirety or part of a PPDU typeused in the EHT system. For example, the example of FIG. 10 may be usedfor both of a single-user (SU) mode and a multi-user (MU) mode. In otherwords, the PPDU of FIG. 10 may be a PPDU for one receiving STA or aplurality of receiving STAs. When the PPDU of FIG. 10 is used for atrigger-based (TB) mode, the EHT-SIG of FIG. 10 may be omitted. In otherwords, an STA which has received a trigger frame for uplink-MU (UL-MU)may transmit the PPDU in which the EHT-SIG is omitted in the example ofFIG. 10 .

In FIG. 10 , an L-STF to an EHT-LTF may be called a preamble or aphysical preamble, and may begenerated/transmitted/received/obtained/decoded in a physical layer.

A subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, andEHT-SIG fields of FIG. 10 may be determined as 312.5 kHz, and asubcarrier spacing of the EHT-STF, EHT-LTF, and Data fields may bedetermined as 78.125 kHz. That is, a tone index (or subcarrier index) ofthe L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields may beexpressed in unit of 312.5 kHz, and a tone index (or subcarrier index)of the EHT-STF, EHT-LTF, and Data fields may be expressed in unit of78.125 kHz.

In the PPDU of FIG. 10 , the L-LTE and the L-STF may be the same asthose in the conventional fields.

The L-SIG field of FIG. 10 may include, for example, bit information of24 bits. For example, the 24-bit information may include a rate field of4 bits, a reserved bit of 1 bit, a length field of 12 bits, a parity bitof 1 bit, and a tail bit of 6 bits. For example, the length field of 12bits may include information related to a length or time duration of aPPDU. For example, the length field of 12 bits may be determined basedon a type of the PPDU. For example, when the PPDU is a non-HT, HT, VHTPPDU or an EHT PPDU, a value of the length field may be determined as amultiple of 3. For example, when the PPDU is an HE PPDU, the value ofthe length field may be determined as “a multiple of 3”+1 or “a multipleof 3”+2. In other words, for the non-HT, HT, VHT PPDI or the EHT PPDU,the value of the length field may be determined as a multiple of 3, andfor the HE PPDU, the value of the length field may be determined as “amultiple of 3”+1 or “a multiple of 3”+2.

For example, the transmitting STA may apply BCC encoding based on a 1/2coding rate to the 24-bit information of the L-SIG field. Thereafter,the transmitting STA may obtain a BCC coding bit of 48 bits. BPSKmodulation may be applied to the 48-bit coding bit, thereby generating48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols topositions except for a pilot subcarrier{subcarrier index −21, −7, +7,+21} and a DC subcarrier {subcarrier index 0}. As a result, the 48 BPSKsymbols may be mapped to subcarrier indices −26 to −22, −20 to −8, −6 to−1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA mayadditionally map a signal of {−1, −1, −1, 1} to a subcarrier index{−28,−27, +27, +28}. The aforementioned signal may be used for channelestimation on a frequency domain corresponding to {−28, −27, +27, +28}.

The transmitting STA may generate an RL-SIG generated in the same manneras the L-SIG. BPSK modulation may be applied to the RL-SIG. Thereceiving STA may know that the RX PPDU is the HE PPDU or the EHT PPDU,based on the presence of the RL-SIG.

A universal SIG (U-SIG) may be inserted after the RL-SIG of FIG. 10 .The U-SIB may be called in various terms such as a first SIG field, afirst SIG, a first type SIG, a control signal, a control signal field, afirst (type) control signal, or the like.

The U-SIG may include information of N bits, and may include informationfor identifying a type of the EHT PPDU. For example, the U-SIG may beconfigured based on two symbols (e.g., two contiguous OFDM symbols).Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4μs. Each symbol of the U-SIG may be used to transmit the 26-bitinformation. For example, each symbol of the U-SIG may betransmitted/received based on 52 data tomes and 4 pilot tones.

Through the U-SIG (or U-SIG field), for example, A-bit information(e.g., 52 un-coded bits) may be transmitted. A first symbol of the U-SIGmay transmit first X-bit information (e.g., 26 un-coded bits) of theA-bit information, and a second symbol of the U-SIB may transmit theremaining Y-bit information (e.g. 26 un-coded bits) of the A-bitinformation. For example, the transmitting STA may obtain 26 un-codedbits included in each U-SIG symbol. The transmitting STA may performconvolutional encoding (i.e., BCC encoding) based on a rate of R=1/2 togenerate 52-coded bits, and may perform interleaving on the 52-codedbits. The transmitting STA may perform BPSK modulation on theinterleaved 52-coded bits to generate 52 BPSK symbols to be allocated toeach U-SIG symbol. One U-SIG symbol may be transmitted based on 65 tones(subcarriers) from a subcarrier index −28 to a subcarrier index +28,except for a DC index 0. The 52 BPSK symbols generated by thetransmitting STA may be transmitted based on the remaining tones(subcarriers) except for pilot tones, i.e., tones −21, −7, +7, +21.

For example, the A-bit information (e.g., 52 un-coded bits) generated bythe U-SIG may include a CRC field (e.g., a field having a length of 4bits) and a tail field (e.g., a field having a length of 6 bits). TheCRC field and the tail field may be transmitted through the secondsymbol of the U-SIG. The CRC field may be generated based on 26 bitsallocated to the first symbol of the U-SIG and the remaining 16 bitsexcept for the CRC/tail fields in the second symbol, and may begenerated based on the conventional CRC calculation algorithm. Inaddition, the tail field may be used to terminate trellis of aconvolutional decoder, and may be set to, for example, “000000”.

The A-bit information (e.g., 52 un-coded bits) transmitted by the U-SIG(or U-SIG field) may be divided into version-independent bits andversion-dependent bits. For example, the version-independent bits mayhave a fixed or variable size. For example, the version-independent bitsmay be allocated only to the first symbol of the U-SIG, or theversion-independent bits may be allocated to both of the first andsecond symbols of the U-SIG. For example, the version-independent bitsand the version-dependent bits may be called in various terms such as afirst control bit, a second control bit, or the like.

For example, the version-independent bits of the U-SIG may include a PHYversion identifier of 3 bits. For example, the PHY version identifier of3 bits may include information related to a PHY version of a TX/RX PPDU.For example, a first value of the PHY version identifier of 3 bits mayindicate that the TX/RX PPDU is an EHT PPDU. In other words, when thetransmitting STA transmits the EHT PPDU, the PHY version identifier of 3bits may be set to a first value. In other words, the receiving STA maydetermine that the RX PPDU is the EHT PPDU, based on the PHY versionidentifier having the first value.

For example, the version-independent bits of the U-SIG may include aUL/DL flag field of 1 bit. A first value of the UL/DL flag field of 1bit relates to UL communication, and a second value of the UL/DL flagfield relates to DL communication.

For example, the version-independent bits of the U-SIG may includeinformation related to a TXOP length and information related to a BSScolor ID.

For example, when the EHT PPDU is divided into various types (e.g.,various types such as an EHT PPDU related to an SU mode, an EHT PPDUrelated to a MU mode, an EHT PPDU related to a TB mode, an EHT PPDUrelated to extended range transmission, or the like), informationrelated to the type of the EHT PPDU may be included in theversion-dependent bits of the U-SIG.

For example, the U-SIG may include: 1) a bandwidth field includinginformation related to a bandwidth; 2) a field including informationrelated to an MCS scheme applied to EHT-SIG; 3) an indication fieldincluding information regarding whether a dual subcarrier modulation(DCM) scheme is applied to EHT-SIG; 4) a field including informationrelated to the number of symbol used for EHT-SIG; 5) a field includinginformation regarding whether the EHT-SIG is generated across a fullband; 6) a field including information related to a type of EHT-LTF/STF;and 7) information related to a field indicating an EHT-LTF length and aCP length.

Preamble puncturing may be applied to the PPDU of FIG. 10 . The preamblepuncturing implies that puncturing is applied to part (e.g., a secondary20 MHz band) of the full band. For example, when an 80 MHz PPDU istransmitted, an STA may apply puncturing to the secondary 20 MHz bandout of the 80 MHz band, and may transmit a PPDU only through a primary20 MHz band and a secondary 40 MHz band.

For example, a pattern of the preamble puncturing may be configured inadvance. For example, when a first puncturing pattern is applied,puncturing may be applied only to the secondary 20 MHz band within the80 MHz band. For example, when a second puncturing pattern is applied,puncturing may be applied to only any one of two secondary 20 MHz bandsincluded in the secondary 40 MHz band within the 80 MHz band. Forexample, when a third puncturing pattern is applied, puncturing may beapplied to only the secondary 20 MHz band included in the primary 80 MHzband within the 160 MHz band (or 80+80 MHz band). For example, when afourth puncturing is applied, puncturing may be applied to at least one20 MHz channel not belonging to a primary 40 MHz band in the presence ofthe primary 40 MHz band included in the 80 MHz band within the 160 MHzband (or 80+80 MHz band).

Information related to the preamble puncturing applied to the PPDU maybe included in U-SIG and/or EHT-SIG. For example, a first field of theU-SIG may include information related to a contiguous bandwidth, andsecond field of the U-SIG may include information related to thepreamble puncturing applied to the PPDU.

For example, the U-SIG and the EHT-SIG may include the informationrelated to the preamble puncturing, based on the following method. Whena bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be configuredindividually in unit of 80 MHz. For example, when the bandwidth of thePPDU is 160 MHz, the PPDU may include a first U-SIG for a first 80 MHzband and a second U-SIG for a second 80 MHz band. In this case, a firstfield of the first U-SIG may include information related to a 160 MHzbandwidth, and a second field of the first U-SIG may include informationrelated to a preamble puncturing (i.e., information related to apreamble puncturing pattern) applied to the first 80 MHz band. Inaddition, a first field of the second U-SIG may include informationrelated to a 160 MHz bandwidth, and a second field of the second U-SIGmay include information related to a preamble puncturing (i.e.,information related to a preamble puncturing pattern) applied to thesecond 80 MHz band. Meanwhile, an EHT-SIG contiguous to the first U-SIGmay include information related to a preamble puncturing applied to thesecond 80 MHz band (i.e., information related to a preamble puncturingpattern), and an EHT-SIG contiguous to the second U-SIG may includeinformation related to a preamble puncturing (i.e., information relatedto a preamble puncturing pattern) applied to the first 80 MHz band.

Additionally or alternatively, the U-SIG and the EHT-SIG may include theinformation related to the preamble puncturing, based on the followingmethod. The U-SIG may include information related to a preamblepuncturing (i.e., information related to a preamble puncturing pattern)for all bands. That is, the EHT-SIG may not include the informationrelated to the preamble puncturing, and only the U-SIG may include theinformation related to the preamble puncturing (i.e., the informationrelated to the preamble puncturing pattern).

The U-SIG may be configured in unit of 20 MHz. For example, when an 80MHz PPDU is configured, the U-SIG may be duplicated. That is, fouridentical U-SIGs may be included in the 80 MHz PPDU. PPDUs exceeding an80 MHz bandwidth may include different U-SIGs.

The U-SIG may be configured in unit of 20 MHz. For example, when an 80MHz PPDU is configured, the U-SIG may be duplicated. That is, fouridentical U-SIGs may be included in the 80 MHz PPDU. PPDUs exceeding an80 MHz bandwidth may include different U-SIGs.

The EHT-SIG of FIG. 10 may include control information for the receivingSTA. The EHT-SIG may be transmitted through at least one symbol, and onesymbol may have a length of 4 μs. Information related to the number ofsymbols used for the EHT-SIG may be included in the U-SIG.

The EHT-SIG may include a technical feature of the HE-SIG-B describedwith reference to FIG. 8 and FIG. 9 . For example, the EHT-SIG mayinclude a common field and a user-specific field as in the example ofFIG. 8 . The common field of the EHT-SIG may be omitted, and the numberof user-specific fields may be determined based on the number of users.

As in the example of FIG. 8 , the common field of the EHT-SIG and theuser-specific field of the EHT-SIG may be individually coded. One userblock field included in the user-specific field may include informationfor two users, but a last user block field included in the user-specificfield may include information for one user. That is, one user blockfield of the EHT-SIG may include up to two user fields. As in theexample of FIG. 9 , each user field may be related to MU-MIMOallocation, or may be related to non-MU-MIMO allocation.

As in the example of FIG. 8 , the common field of the EHT-SIG mayinclude a CRC bit and a tail bit. A length of the CRC bit may bedetermined as 4 bits. A length of the tail bit may be determined as 6bits, and may be set to ‘000000’.

As in the example of FIG. 8 , the common field of the EHT-SIG mayinclude RU allocation information. The RU allocation information mayimply information related to a location of an RU to which a plurality ofusers (i.e., a plurality of receiving STAs) are allocated. The RUallocation information may be configured in unit of 8 bits (or N bits),as in Table 1. The example of Table 5 to Table 7 is an example of 8-bit(or N-bit) information for various RU allocations. An index shown ineach table may be modified, and some entries in Table 5 to Table 7 maybe omitted, and entries (not shown) may be added.

The example of Table 5 to Table 7 relates to information related to alocation of an RU allocated to a 20 MHz band. For example, ‘an index 0’of Table 5 may be used in a situation where nine 26-RUs are individuallyallocated (e.g., in a situation where nine 26-RUs shown in FIG. 5 areindividually allocated).

Meanwhile, a plurality or RUs may be allocated to one STA in the EHTsystem. For example, regarding ‘an index 60’ of Table 6, one 26-RU maybe allocated for one user (i.e., receiving STA) to the leftmost side ofthe 20 MHz band, one 26-RU and one 52-RU may be allocated to the rightside thereof, and five 26-RUs may be individually allocated to the rightside thereof.

TABLE 5 Number Indices #1 #2 #3 #4 #5 #6 #7 #8 #9 of entries 0 26 26 2626 26 26 26 26 26 1 1 26 26 26 26 26 26 26 52 1 2 26 26 26 26 26 52 2626 1 3 26 26 26 26 26 52 52 1 4 26 26 52 26 26 26 26 26 1 5 26 26 52 2626 26 52 1 6 26 26 52 26 52 26 26 1 7 26 26 52 26 52 52 1 8 52 26 26 2626 26 26 26 1 9 52 26 26 26 26 26 52 1 10 52 26 26 26 52 26 26 1 11 5226 26 26 52 52 1 12 52 52 26 26 26 26 26 1 13 52 52 26 26 26 52 1 14 5252 26 52 26 26 1 15 52 52 26 52 52 1 16 26 26 26 26 26 106 1 17 26 26 5226 106 1 18 52 26 26 26 106 1 19 52 52 26 106 1

TABLE 6 Number Indices #1 #2 #3 #4 #5 #6 #7 #8 #9 of entries 20 106 2626 26 26 26 1 21 106 26 26 26 52 1 22 106 26 52 26 26 1 23 106 26 52 521 24 52 52 — 52 52 1 25 242-tone RU empty (with zero users) 1 26 106 26106 1 27-34 242 8 35-42 484 8 43-50 996 8 51-58 2*996 8 59 26 26 26 2626 52 + 26 26 1 60 26 26 + 52 26 26 26 26 26 1 61 26 26 + 52 26 26 26 521 62 26 26 + 52 26 52 26 26 1 63 26 26 52 26 52 + 26 26 1 64 26 26 + 5226 52 + 26 26 1 65 26 26 + 52 26 52 52 1

TABLE 7 66 52 26 26 26 52 + 26 26 1 67 52 52 26 52 + 26 26 1 68 52 52 +26 52 52 1 69 26 26 26 26 26 + 106 1 70 26 26 + 52 26 106 1 71 26 26 5226 + 106 1 72 26 26 + 52 26 + 106 1 73 52 26 26 26 + 106 1 74 52 52 26 +106 1 75 106 + 26 26 26 26 26 1 76 106 + 26 26 26 52 1 77 106 + 26 52 2626 1 78 106 26 52 + 26 26 1 79 106 + 26 52 + 26 26 1 80 106 + 26 52 52 181 106 + 26 106 1 82 106 26 + 106 1

A mode in which the common field of the EHT-SIG is omitted may besupported. The mode in the common field of the EHT-SIG is omitted may becalled a compressed mode. When the compressed mode is used, a pluralityof users (i.e., a plurality of receiving STAs) may decode the PPDU(e.g., the data field of the PPDU), based on non-OFDMA. That is, theplurality of users of the EHT PPDU may decode the PPDU (e.g., the datafield of the PPDU) received through the same frequency band. Meanwhile,when a non-compressed mode is used, the plurality of users of the EHTPPDU may decode the PPDU (e.g., the data field of the PPDU), based onOFDMA. That is, the plurality of users of the EHT PPDU may receive thePPDU (e.g., the data field of the PPDU) through different frequencybands.

The EHT-SIG may be configured based on various MCS schemes. As describedabove, information related to an MCS scheme applied to the EHT-SIG maybe included in U-SIG. The EHT-SIG may be configured based on a DCMscheme. For example, among N data tones (e.g., 52 data tones) allocatedfor the EHT-SIG, a first modulation scheme may be applied to half ofconsecutive tones, and a second modulation scheme may be applied to theremaining half of the consecutive tones. That is, a transmitting STA mayuse the first modulation scheme to modulate specific control informationthrough a first symbol and allocate it to half of the consecutive tones,and may use the second modulation scheme to modulate the same controlinformation by using a second symbol and allocate it to the remaininghalf of the consecutive tones. As described above, information (e.g., a1-bit field) regarding whether the DCM scheme is applied to the EHT-SIGmay be included in the U-SIG. An HE-STF of FIG. 10 may be used forimproving automatic gain control estimation in a multiple input multipleoutput (MIMO) environment or an OFDMA environment. An HE-LTF of FIG. 10may be used for estimating a channel in the MIMO environment or theOFDMA environment.

The EHT-STF of FIG. 10 may be set in various types. For example, a firsttype of STF (e.g., 1×STF) may be generated based on a first type STFsequence in which a non-zero coefficient is arranged with an interval of16 subcarriers. An STF signal generated based on the first type STFsequence may have a period of 0.8 μs, and a periodicity signal of 0.8 μsmay be repeated 5 times to become a first type STF having a length of 4μs. For example, a second type of STF (e.g., 2×STF) may be generatedbased on a second type STF sequence in which a non-zero coefficient isarranged with an interval of 8 subcarriers. An STF signal generatedbased on the second type STF sequence may have a period of 1.6 μs, and aperiodicity signal of 1.6 μs may be repeated 5 times to become a secondtype STF having a length of 8 μs. Hereinafter, an example of a sequencefor configuring an EHT-STF (i.e., an EHT-STF sequence) is proposed. Thefollowing sequence may be modified in various ways.

The EHT-STF may be configured based on the following sequence M.

M={−1,−1,−1,1,1,1,−1,1,1,1,−1,1,1,−1,1}  <Equation 1>

The EHT-STF for the 20 MHz PPDU may be configured based on the followingequation. The following example may be a first type (i.e., 1×STF)sequence. For example, the first type sequence may be included in not atrigger-based (TB) PPDU but an EHT-PPDU. In the following equation,(a:b:c) may imply a duration defined as b tone intervals (i.e., asubcarrier interval) from a tone index (i.e., subcarrier index) ‘a’ to atone index ‘c’. For example, the equation 2 below may represent asequence defined as 16 tone intervals from a tone index −112 to a toneindex 112. Since a subcarrier spacing of 78.125 kHz is applied to theEHT-STR, the 16 tone intervals may imply that an EHT-STF coefficient (orelement) is arranged with an interval of 78.125*16=1250 kHz. Inaddition, * implies multiplication, and sqrt( ) implies a square root.In addition, j implies an imaginary number.

EHT-STF(−112:16:112)={M}*(1+j)/sqrt(2)

EHT-STF(0)=0  <Equation 2>

The EHT-STF for the 40 MHz PPDU may be configured based on the followingequation. The following example may be the first type (i.e., 1×STF)sequence.

EHT-STF(−240:16:240)={M,0,−M}*(1+j)/sqrt(2)  <Equation 3>

The EHT-STF for the 80 MHz PPDU may be configured based on the followingequation. The following example may be the first type (i.e., 1×STF)sequence.

EHT-STF(−496:16:496)={M,1,−M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation 4>

The EHT-STF for the 160 MHz PPDU may be configured based on thefollowing equation. The following example may be the first type (i.e.,1×STF) sequence.

EHT-STF(−1008:16:1008)={M,1,−M,0,−M,1,−M,0,−M,−1,M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation5>

In the EHT-STF for the 80+80 MHz PPDU, a sequence for lower 80 MHz maybe identical to Equation 4. In the EHT-STF for the 80+80 MHz PPDU, asequence for upper 80 MHz may be configured based on the followingequation.

EHT−STF(−496:16:496)={−M,−1,M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation 6>

Equation 7 to Equation 11 below relate to an example of a second type(i.e., 2×STF) sequence.

EHT-STF(−120:8:120)={M,0,−M}*(1+j)/sqrt(2)  <Equation 7>

The EHT-STF for the 40 MHz PPDU may be configured based on the followingequation.

EHT-STF(−248:8:248)={M,−1,−M,0,M,−1,M}*(1+j)/sqrt(2)

EHT-STF(−248)=0

EHT-STF(248)=0  <Equation 8>

The EHT-STF for the 80 MHz PPDU may be configured based on the followingequation.

EHT-STF(−504:8:504)={M,−1,M,−1,−M,−1,M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)  <Equation9>

The EHT-STF for the 160 MHz PPDU may be configured based on thefollowing equation.

EHT-STF(−1016:16:1016)={M,−1,M,−1,−M,−1,M,0,−M,1,M,1,−M,1,−M,0,−M,1,−M,1,M,1,−M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)

EHT-STF(−8)=0, EHT-STF(8)=0,

EHT-STF(−1016)=0, EHT-STF(1016)=0  <Equation 10>

In the EHT-STF for the 80+80 MHz PPDU, a sequence for lower 80 MHz maybe identical to Equation 9. In the EHT-STF for the 80+80 MHz PPDU, asequence for upper 80 MHz may be configured based on the followingequation.

EHT-STF(−504:8:504)={−M,1,−M,1,M,1,−M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)

EHT-STF(−504)=0,

EHT-STF(504)=0  <Equation 11>

The EHT-LTF may have first, second, and third types (i.e., 1×, 2×,4×LTF). For example, the first/second/third type LTF may be generatedbased on an LTF sequence in which a non-zero coefficient is arrangedwith an interval of 4/2/1 subcarriers. The first/second/third type LTFmay have a time length of 3.2/6.4/12.8 μs. In addition, a GI (e.g.,0.8/1/6/3.2 μs) having various lengths may be applied to thefirst/second/third type LTF.

Information related to a type of STF and/or LTF (information related toa GI applied to LTF is also included) may be included in a SIG-A fieldand/or SIG-B field or the like of FIG. 10 .

A PPDU (e.g., EHT-PPDU) of FIG. 10 may be configured based on theexample of FIG. 5 and FIG. 6 .

For example, an EHT PPDU transmitted on a 20 MHz band, i.e., a 20 MHzEHT PPDU, may be configured based on the RU of FIG. 5 . That is, alocation of an RU of EHT-STF, EHT-LTF, and data fields included in theEHT PPDU may be determined as shown in FIG. 5 .

An EHT PPDU transmitted on a 40 MHz band, i.e., a 40 MHz EHT PPDU, maybe configured based on the RU of FIG. 6 . That is, a location of an RUof EHT-STF, EHT-LTF, and data fields included in the EHT PPDU may bedetermined as shown in FIG. 6 .

Since the RU location of FIG. 6 corresponds to 40 MHz, a tone-plan for80 MHz may be determined when the pattern of FIG. 6 is repeated twice.That is, an 80 MHz EHT PPDU may be transmitted based on a new tone-planin which not the RU of FIG. 7 but the RU of FIG. 6 is repeated twice.

When the pattern of FIG. 6 is repeated twice, 23 tones (i.e., 11 guardtones+12 guard tones) may be configured in a DC region. That is, atone-plan for an 80 MHz EHT PPDU allocated based on OFDMA may have 23 DCtones. Unlike this, an 80 MHz EHT PPDU allocated based on non-OFDMA(i.e., a non-OFDMA full bandwidth 80 MHz PPDU) may be configured basedon a 996-RU, and may include 5 DC tones, 12 left guard tones, and 11right guard tones.

A tone-plan for 160/240/320 MHz may be configured in such a manner thatthe pattern of FIG. 6 is repeated several times.

The PPDU of FIG. 10 may be determined (or identified) as an EHT PPDUbased on the following method.

A receiving STA may determine a type of an RX PPDU as the EHT PPDU,based on the following aspect. For example, the RX PPDU may bedetermined as the EHT PPDU: 1) when a first symbol after an L-LTF signalof the RX PPDU is a BPSK symbol; 2) when RL-SIG in which the L-SIG ofthe RX PPDU is repeated is detected; and 3) when a result of applying“modulo 3” to a value of a length field of the L-SIG of the RX PPDU isdetected as “0”. When the RX PPDU is determined as the EHT PPDU, thereceiving STA may detect a type of the EHT PPDU (e.g., anSU/MU/Trigger-based/Extended Range type), based on bit informationincluded in a symbol after the RL-SIG of FIG. 10 . In other words, thereceiving STA may determine the RX PPDU as the EHT PPDU, based on: 1) afirst symbol after an L-LTF signal, which is a BPSK symbol; 2) RL-SIGcontiguous to the L-SIG field and identical to L-SIG; 3) L-SIG includinga length field in which a result of applying “modulo 3” is set to “0”;and 4) a 3-bit PHY version identifier of the aforementioned U-SIG (e.g.,a PHY version identifier having a first value).

For example, the receiving STA may determine the type of the RX PPDU asthe EHT PPDU, based on the following aspect. For example, the RX PPDUmay be determined as the HE PPDU: 1) when a first symbol after an L-LTFsignal is a BPSK symbol; 2) when RL-SIG in which the L-SIG is repeatedis detected; and 3) when a result of applying “modulo 3” to a value of alength field of the L-SIG is detected as “1” or “2”.

For example, the receiving STA may determine the type of the RX PPDU asa non-HT, HT, and VHT PPDU, based on the following aspect. For example,the RX PPDU may be determined as the non-HT, HT, and VHT PPDU: 1) when afirst symbol after an L-LTF signal is a BP SK symbol; and 2) when RL-SIGin which L-SIG is repeated is not detected. In addition, even if thereceiving STA detects that the RL-SIG is repeated, when a result ofapplying “modulo 3” to the length value of the L-SIG is detected as “0”,the RX PPDU may be determined as the non-HT, HT, and VHT PPDU.

In the following example, a signal represented as a (TX/RX/UL/DL)signal, a (TX/RX/UL/DL) frame, a (TX/RX/UL/DL) packet, a (TX/RX/UL/DL)data unit, (TX/RX/UL/DL) data, or the like may be a signaltransmitted/received based on the PPDU of FIG. 10 . The PPDU of FIG. 10may be used to transmit/receive frames of various types. For example,the PPDU of FIG. 10 may be used for a control frame. An example of thecontrol frame may include a request to send (RTS), a clear to send(CTS), a power save-poll (PS-poll), BlockACKReq, BlockAck, a null datapacket (NDP) announcement, and a trigger frame. For example, the PPDU ofFIG. 10 may be used for a management frame. An example of the managementframe may include a beacon frame, a (re-)association request frame, a(re-)association response frame, a probe request frame, and a proberesponse frame. For example, the PPDU of FIG. 10 may be used for a dataframe. For example, the PPDU of FIG. 10 may be used to simultaneouslytransmit at least two or more of the control frames, the managementframe, and the data frame.

FIG. 11 illustrates an example of a modified transmission device and/orreceiving device of the present specification.

Each device/STA of the sub-figure (a)/(b) of FIG. 1 may be modified asshown in FIG. 11 . A transceiver 630 of FIG. 11 may be identical to thetransceivers 113 and 123 of FIG. 1 . The transceiver 630 of FIG. 11 mayinclude a receiver and a transmitter.

A processor 610 of FIG. 11 may be identical to the processors 111 and121 of FIG. 1 . Alternatively, the processor 610 of FIG. 11 may beidentical to the processing chips 114 and 124 of FIG. 1 .

A memory 620 of FIG. 11 may be identical to the memories 112 and 122 ofFIG. 1 . Alternatively, the memory 620 of FIG. 11 may be a separateexternal memory different from the memories 112 and 122 of FIG. 1 .

Referring to FIG. 11 , a power management module 611 manages power forthe processor 610 and/or the transceiver 630. A battery 612 suppliespower to the power management module 611. A display 613 outputs a resultprocessed by the processor 610. A keypad 614 receives inputs to be usedby the processor 610. The keypad 614 may be displayed on the display613. A SIM card 615 may be an integrated circuit which is used tosecurely store an international mobile subscriber identity (IMSI) andits related key, which are used to identify and authenticate subscriberson mobile telephony devices such as mobile phones and computers.

Referring to FIG. 11 , a speaker 640 may output a result related to asound processed by the processor 610. A microphone 641 may receive aninput related to a sound to be used by the processor 610.

1. Subchannel Selective Transmission (SST) Mechanism and LTF Sequence

The HE STA supporting the HE SST operation shall setdot11HESbchannelSelectiveTransmissionImplemented to true and set the HESubchannel selective transmission support field of the HE Capabilitieselement transmitted by itself to 1.

The HE STA that does not support the HE SST operation shall set the HESubchannel Selective Transmission Support field to 0 in the HECapabilities element transmitted by itself.

Target wake time (TWT) allows the AP to manage activity in the BSS tominimize contention between STAs and reduce the time required for STAsusing power saving mode to stay awake. This is achieved by allocatingSTAs to operate at non-overlapping times and/or frequencies and focusingframe exchanges on predefined service periods. The HE STA negotiatesindividual TWT agreements with other HE STAs.

The HE SST non-AP STA and the HE SST AP may set the SST operation bynegotiating the trigger activation TWT defined in the individual TWTcontract, except for the following.

-   -   The TWT request may have a TWT channel field with a maximum of 1        bit set to 1 to indicate a secondary channel requested to        include an RU assignment addressed to a HE SST non-AP STA that        is a 20 MHz operating STA.    -   The TWT request may have a TWT channel field with all four LSBs        or all four MSBs set to 1 to indicate whether the primary 80 MHz        channel or the secondary 80 MHz channel is requested to include        the RU allocation addressed to the HE SST non-AP STA that is the        80 MHz operating STA.    -   The TWT response shall have a TWT channel field with a maximum        of 1 bit set to 1 to indicate the secondary channel that will        contain the RU assignment addressed to the HE SST non-AP STA        that is the 20 MHz operating STA.    -   The TWT response shall have a TWT channel field including all        four LSBs or all four MSBs indicating whether the primary 80 MHz        channel or the secondary 80 MHz channel includes the RU        allocation addressed to the HE SST non-AP STA that is the 80 MHz        operating STA.

The HE SST AP and the HE SST non-AP STA implicitly terminate the triggeractivation TWT if HE SST AP changes the working channel or channel widthand the secondary channel of the trigger-activated TWT is not within thenew working channel or channel width.

The HE SST non-AP STA follows the rules of the individual TWT contractto exchange frames with the HE SST AP during trigger activation TWT SP.However, the following conditions are excluded.

-   -   The STA shall be available on the subchannel indicated in the        TWT channel field of the TWT response at the TWT start time.    -   The STA shall not access the medium of the subchannel using DCF        or EDCAF.    -   The STA shall not respond to a trigger frame addressed to it        unless it performs CCA until a frame capable of setting NAV is        detected, or until a period equal to NAVSyncDelay occurs        (whichever is earlier).    -   When the STA receives a PPDU in a subchannel, it must update the        NAV according to two NAV updates.

That is, according to the SST mechanism, the HE SST AP and the HE SSTnon-AP STA may access a specific subchannel (or secondary channel)during the trigger-enabled TWT SP.

2. Examples Applicable to the Present Specification

In the WLAN 802.11 system, in order to increase peak throughput, it isconsidered to use a wider band than the existing 802.11ax or to transmitan increased stream by using more antennas. In addition, a method ofusing various bands by aggregation is also being considered.

In this specification, a structure and configuration method of anAggregated PPDU in which HE PPDU and EHT PPDU are simultaneouslytransmitted under a broadband consideration are proposed.

FIG. 12 is a diagram of a representative Aggregated PPDU.

Referring to FIG. 12 , each Sub-PPDU may be a HE PPDU/EHT PPDU/post-EHT(EHT+) PPDU. However, it may be preferable that the HE PPDU istransmitted within the primary 160 MHz. In addition, it may be desirableto transmit the same type of Sub-PPDU within the primary 160 MHz and thesecondary 160 MHz. By the SST mechanism, each STA can be allocated to aspecific band of 80 MHz or higher, a sub-PPDU for each STA may betransmitted, or each STA may transmit a sub-PPDU in the correspondingband. FIG. 10 shows a representative EHT MU PPDU format.

The advantage of A-PPDU is that when supporting HE/EHT (/EHT+) STAs atthe same time, it can provide simultaneous support by maximizing thePPDU suitable for each STA's version, not the HE PPDU. (EHT or EHT+STAcan also use HE Sub-PPDU within A-PPDU, the corresponding PPDU may belocated in a channel different from the HE Sub-PPDU for the HE STA, andmay be supported together with the HE STA using the MU HE Sub-PPDU inthe same channel). By performing transmission using the A-PPDU in thisway, transmission efficiency can be further increased.

FIG. 13 shows an example of the structure of U-SIG.

The U-SIG is divided into a version independent field and a versiondependent field as shown in FIG. 13 .

Bandwidth field can be used to indicate bandwidth, which can be includedin the version independent field of Universal-SIG (U-SIG). Additionally,in addition to the bandwidth field, a 20 MHz-based preamble puncturingpattern within the corresponding 80 MHz at each 80 MHz may also beindicated. This may help STAs decoding a specific 80 MHz to decode theEHT-SIG. Therefore, assuming that such information is loaded on theU-SIG, the configuration of the U-SIG may change every 80 MHz.

In addition, the version independent field may include a 3-bit versionidentifier indicating a Wi-Fi version after 802.11be and 802.11be, a1-bit DL/UL field, a BSS color, a TXOP duration, and the like, theversion dependent field may include information such as a PPDU type. InU-SIG, two symbols are jointly encoded, and U-SIG consists of 52 datatones and 4 pilot tones for each 20 MHz. Also, U-SIG is modulated in thesame way as HE-SIG-A. That is, the U-SIG is modulated with a BPSK 1/2code rate. In addition, the EHT-SIG may be divided into a common fieldand a user specific field, and may be encoded as a variable MCS. TheEHT-SIG may have a 1 2 1 2 . . . structure in units of 20 MHz as in theexisting 802.11ax (or it may be configured in another structure. Forexample, 1 2 3 4 . . . or 1 2 1 2 3 4 3 4 . . . .). In addition, theEHT-SIG may be configured in units of 80 MHz, and in a bandwidth of 80MHz or more, the EHT-SIG may be duplicated in units of 80 MHz or may beconfigured with different information in units of 80 MHz.

In this specification, when the DL Aggregated PPDU is composed of HESub-PPDU and EHT Sub-PPDU, various configuration methods and structuresof each Sub-PPDU and the entire A-PPDU are proposed.

2.1. Composition of Each Sub-PPDU in Units of 80 MHz

Sub-PPDUs can be configured in units of at least 80 MHz channels. Thatis, within 80 MHz, different Sub-PPDUs may not be mixed. FIG. 14 simplyshows an example of this.

FIG. 14 shows an example of an A-PPDU in which each sub-PPDU isconfigured in units of 80 MHz.

In FIG. 14 , the primary 80 MHz is composed of HE Sub-PPDU, and thesecondary 80 MHz is composed of EHT Sub-PPDU. This is an example, andeach Sub-PPDU can be composed of several 80 MHz combined. However, itmay be preferable that the primary 80 MHz is composed of HE Sub-PPDUs.In addition, in FIG. 14 , each field of the HE Sub-PPDU and the EHTSub-PPDU is aligned, but this is not intended, and the HE Sub-PPDU maybe composed of an SU PPDU (without HE-SIG-B) rather than an MU PPDU.However, the beginning and end of each Sub-PPDU may be the same. Inaddition, each Sub-PPDU may consider preamble puncturing defined in 11ax and 11be. In addition, L-SIG/RL-SIG of HE Sub-PPDU and EHT Sub-PPDUmay be configured as defined in HE and EHT, that is, may be configuredwith different contents (because L_LENGTH definition is different).

In 802.11be, U-SIG or EHT-SIG can be composed of different contents foreach 80 MHz, and considering this, it may be desirable to configure aSub-PPDU in units of 80 MHz. In addition, considering the SST defined inthe existing 802.11ax and applying it to 802.11be as it is, each STA isallocated in units of 80 MHz, and each STA only needs to decode theSub-PPDU transmitted within the corresponding channel, so the structureof FIG. 14 can be desirable.

However, in this embodiment, an error may occur when decoding by a 160MHz capable 11 ax STA. When a 160 MHz capable 802.11ax STA detectssignals in the entire 160 MHz channel, decoding can be performed bycombining L-SIG and HE-SIG-A. In this case, if different Sub-PPDUs aremixed within a specific 160 MHz, decoding errors may occur in the 160MHz capable 802.11ax STAs. In order to overcome this to some extent, theL-SIG/RL-SIG of the EHT Sub-PPDU can be simply configured with the sameL-SIG/RL-SIG as the HE Sub-PPDU. Additionally, when HE Sub-PPDU and EHTSub-PPDU are mixed within 160 MHz, decoding may be applied only to theEHT Sub-PPDU within 160 MHz. However, this may cause a problem in thatEHT STAs (regardless of whether they participate in transmission or not)determine the EHT Sub-PPDU as the HE Sub-PPDU. In addition, when a 160MHz capable 802.11ax STA performs HE-SIG-A decoding, an error may occurdue to combining U-SIG.

In addition, if SST is not considered, problems may occur in the EHT STAreceiving data from the EHT Sub-PPDU. The reason is that it can beassumed that the corresponding EHT STA is watching the primary 20 MHz(or 40/80 MHz), and in this case, information on the EHT Sub-PPDU cannotbe obtained within the HE Sub-PPDU. To solve this problem, the A-PPDUcan be indicated by setting the Reserved Bit 4 of all L-SIGs or RL-SIGsin the HE Sub-PPDU to 1, but it can be difficult to implement becausethe EHT STA must switch immediately after decoding Also, since there isno information about where to switch to, this can also be a problem. Inaddition, in terms of implementation, it may be desirable that ReservedBit 4 of L-SIG or RL-SIG is always set to 0.

2.2. Insert Pre-Padding Field into EHT Sub-PPDU

As in 2.1, the Sub-PPDU structure in units of 80 MHz channels can beconsidered, and a Pre-Padding field of a specific length can be insertedbefore the EHT Sub-PPDU in the corresponding A-PPDU. The correspondingPre-Padding field may consist of a sequence having a smallcross-correlation with an L-STF and an L-LTF. EHT STAs may detect this,and in this case, information for the EHT STA may be loaded. Inaddition, the pre-padding field may always have the same specificstructure, but may have a different structure depending on whether ornot SST is applied.

In addition, the Pre-Padding field may be composed of a specific fieldother than L-STF among fields of the Sub-PPDU. This may be desirablebecause it can minimize additional hardware implementation forgenerating a Pre-Padding field. For example, the pre-padding field maybe configured using L-LTF, and may have a structure in which L-LTF isrepeated once or several times. Or, the Pre-Padding field may have astructure in which L-SIG/RL-SIG/U-SIG/EHT-SIG/EHT-STF/EHT-LTF/Data,which are several fields used in the EHT Sub-PPDU, are repeated once orseveral times (in case of data, one symbol or several symbols can beused). The Pre-Padding field includesL-SIG/RL-SIG/HE-SIG-A/HE-SIG-B/HE-STF/HE-LTF/Data, which are variousfields used in the HE Sub-PPDU, once or several times (in case of data,one symbol or several symbols can be used).

The following is a proposal for a Pre-Padding field according to whetheror not SST is applied.

2.2.1. When SST is Applied

If SST is applied, only the combining problem for the 160 MHz capable HESTA needs to be solved through the Pre-Padding field. That is, if thePre-Padding field is inserted before the EHT Sub-PPDU in A-PPDUtransmission, even if HE Sub-PPDU and EHT Sub-PPDU are mixed within aspecific 160 MHz channel, 160 MHz capable HE STA cannot detect Wi-Fisignal in the corresponding channel due to Pre-Padding of EHT Sub-PPDU.Since decoding can be performed by combining only the L-SIG and HE-SIG-Awithin the HE Sub-PPDU, an error problem caused by combining can besolved. Therefore, when different sub-PPDUs are mixed within 160 MHz,pre-padding can be used. Conversely, when different sub-PPDUs are usedfor every 160 MHz channel, the pre-padding field may not be used.Additionally, a specific 160 MHz channel is composed of the same versionof Sub-PPDU (e.g. EHT Sub-PPDU). In a specific 160 MHz, in a 320 MHz (orhigher) A-PPDU transmission situation in which HE Sub-PPDU and EHTSub-PPDU are mixed, Pre-Padding may be inserted only in the EHT Sub-PPDUwithin 160 MHz that transmits the mixed Sub-PPDU. In this case, this maynot be desirable because the fields of the EHT Sub-PPDU with pre-paddinginsertion and the EHT Sub-PPDU without insertion are not aligned, so incase of transmission of such A-PPDU, mixed sub-PPDU is transmitted. Itmay be desirable to insert Pre-Padding into all EHT Sub-PPDUs in otherchannels as well as a specific 160 MHz channel.

In addition, since there is no switching issue of STAs, the Pre-Paddingfield may not need to have a long length. For example, the Pre-Paddingfield may have a length of 4 us (CCA period) or may be inserted only upto L-STF or L-LTF of the HE Sub-PPDU.

FIG. 15 is an example of an A-PPDU structure and shows a case in whichPre-Padding is inserted up to the L-LTF of the HE Sub-PPDU.

FIG. 15 shows an example of an A-PPDU in which each sub-PPDU isconfigured in units of 80 MHz.

In FIG. 15 , the primary 80 MHz is composed of HE Sub-PPDU, and thesecondary 80 MHz is composed of EHT Sub-PPDU. This is an example, andeach Sub-PPDU can be composed of several 80 MHz combined. However, itmay be preferable that the primary 80 MHz is composed of HE Sub-PPDUs.Also in FIG. 15 , alignment between L-SIG/RL-SIG of HE Sub-PPDU andL-STF/L-LTF of EHT Sub-PPDU is not intended. The HE Sub-PPDU may consistof an SU PPDU (no HE-SIG-B) rather than an MU PPDU. However, thebeginning and end of each Sub-PPDU may be the same. In addition, eachSub-PPDU may consider preamble puncturing defined in 802.11ax and802.11be. In addition, the L-Length in the L-SIG of the EHT Sub-PPDU maybe set considering the L-SIG part without considering the previous partof the L-SIG. That is, as a result, it can be set to the EHT Sub-PPDUlength after L-SIG. In addition, the L-SIG of the HE Sub-PPDU may beconfigured as defined in HE.

2.2.2. If SST is not Applied

If SST is not applied, the combining problem for the 160 MHz capable HESTA and the channel switching problem of the EHT STA must also be solvedthrough the Pre-Padding field. That is, if SST is not applied, it may bepreferable that the Pre-Padding field is always located before the EHTSub-PPDU when the A-PPDU is transmitted, and the Pre-Padding field mayrequire a longer length than the 2.2.1 proposal.

First, for channel switching of the EHT STA, an indicator for the A-PPDUis required in the HE Sub-PPDU. It can be assumed that the EHT STAreceiving data from the EHT Sub-PPDU is watching the primary 20 MHz (or40/80/160 MHz) (the primary channel is transmitted by the HE Sub-PPDU).In this case, this is because U-SIG can be decoded by performing channelswitching through the following indicators. The AP sets Reserved Bit 4of all L-SIGs or RL-SIGs in the HE Sub-PPDU to 1 to indicate the A-PPDU,or when the HE Sub-PPDU is composed of the SU PPDU, the AP can indicatethe A-PPDU by setting Reserved Bit 14 of all HE-SIG-A1 or Reserved Bit14 of HE-SIG-A2 to 0. In addition, when the HE Sub-PPDU is configured asan MU PPDU, the A-PPDU can be indicated by setting the Reserved Bit 7 ofHE-SIG-A2 to 0. However, this method can be problematic because there isno information about which channel to switch to. Therefore, it ispossible to indicate which channel to switch to by combining severalreserved bits. For example, information may be indicated using a totalof 2 bits, 1 bit each of reserved bits of L-SIG and HE-SIG-A. SinceL-SIG reserved bit 0 and HE-SIG-A reserved bit 1 are settings in theexisting HE, AP can indicate secondary 80 MHz, MHz corresponding toprimary 80 MHz within secondary 160 MHz, 80 MHz corresponding tosecondary 80 MHz within secondary 160 MHz based on any combination of00, 10, 11 except for this. Since 11 is the setting in HE, AP canindicate secondary 80 MHz, 80 MHz corresponding to primary 80 MHz withinsecondary 160 MHz, and 80 MHz corresponding to secondary 80 MHz withinsecondary 160 MHz based on any combination of 00, 01, and 10 except forthis. Alternatively, the AP may indicate low 80 MHz and high 80 MHzwithin secondary 80 MHz and secondary 160 MHz.

Or, the EHT STA can decide which channel to switch to by using these twopieces of information and by indicating A-PPDU information with one bitamong the BW information of HE-SIG-A and all L-SIG/RL-SIGs in HESub-PPDU or reserved bits of HE-SIG-A. For example, if the BW of the HESub-PPDU is 80 MHz, the EHT STA receiving data from the EHT Sub-PPDU candecode U-SIG by switching to secondary 80 MHz. As another example, ifthe BW of the HE Sub-PPDU is 20/40 MH, the EHT STA receiving data fromthe EHT Sub-PPDU may decode U-SIG by switching to secondary 80 MHz. Asanother example, if the BW of the HE Sub-PPDU is 160 MH, the EHT STAreceiving data from the EHT Sub-PPDU may decode the U-SIG by switchingto secondary 160 MHz.

Additionally, for a simple A-PPDU indication, a situation in which onlyHE Sub-PPDUs are configured in Primary 160 MHz and EHT Sub-PPDUs inSecondary 160 MHz can be considered. In this case, A-PPDU information isindicated by one bit among all L-SIG/RL-SIG or HE-SIG-A reserved bits inthe HE Sub-PPDU, an EHT STA receiving data from the EHT Sub-PPDU maydecode U-SIG by switching to Secondary 160 MHz.

The length of the Pre-Padding field of the EHT Sub-PPDU may varydepending on the PPDU type of the HE Sub-PPDU. If the HE Sub-PPDU is theSU PPDU, it can be determined that the HE-SIG-A is the SU PPDU. Inaddition, HE-SIG-A of the HE SU PPDU does not have STA ID information,but since the HE STA will always be allocated during SU transmission, ifthe HE Sub-PPDU is the SU PPDU, the EHT STA can always switch channelsaccording to the A-PPDU indicator. Therefore, the Pre-Padding field ofthe EHT Sub-PPDU may be inserted up to HE-SIG-A of the HE Sub-PPDU. Inaddition, since the switching time may vary depending on the hardware ofthe EHT STA, a Pre-Padding field with a specific time (alpha) added maybe inserted in consideration of this. Alpha is a value set inconsideration of the hardware capability of the EHT STA, and may be set,for example, considering the switching time of the EHT STA that takesthe longest switching time among the EHT STAB to be switched. FIG. 16 isan example of an A-PPDU structure when the HE Sub-PPDU is an SU PPDU,and Pre-Padding is inserted up to HE-SIG-A+alpha of the HE Sub-PPDU.Additionally, if alpha is less than SIFS or DIFS, alpha may be a sectionin which no signal is loaded.

FIG. 16 shows an example of an A-PPDU in which each sub-PPDU isconfigured in units of 80 MHz.

In FIG. 16 , the primary 80 MHz is composed of HE Sub-PPDU and thesecondary 80 MHz is composed of EHT Sub-PPDU. This is an example, andeach Sub-PPDU can be composed of several 80 MHz combined. However, itmay be preferable that the primary 80 MHz is composed of HE Sub-PPDUs.Also, the beginning and end of each Sub-PPDU may be the same. Inaddition, each Sub-PPDU may consider preamble puncturing defined in802.11ax and 802.11be. In addition, the L-Length in the L-SIG of the EHTSub-PPDU may be set considering the L-SIG part without considering theprevious part of the L-SIG. That is, as a result, it can be set to theEHT Sub-PPDU length after L-SIG. In addition, the L-SIG of the HESub-PPDU may be configured as defined in HE.

If the HE Sub-PPDU is an MU PPDU, there is STA ID information in theuser info field of HE-SIG-B, after decoding the corresponding fields,the EHT STA may switch the channel according to the A-PPDU indicator ifit does not belong. Therefore, the Pre-Padding field of the EHT Sub-PPDUmay be inserted up to HE-SIG-B of the HE Sub-PPDU. In addition, sincethe switching time may vary depending on the hardware of the EHT STA, aPre-Padding field with a specific time (alpha) added may be inserted inconsideration of this. Alpha is a value set in consideration of thehardware capability of the EHT STA, and may be set in consideration of,for example, the switching time of the EHT STA that takes the longestswitching time among the EHT STAB to be switched. FIG. 17 is an exampleof an A-PPDU structure when the HE Sub-PPDU is an MU PPDU, andPre-Padding is inserted up to HE-SIG-B+alpha of the HE Sub-PPDU.Additionally, if alpha is less than SIFS or DIFS, alpha may be a sectionin which no signal is loaded.

FIG. 17 shows an example of an A-PPDU in which each sub-PPDU isconfigured in units of 80 MHz.

In FIG. 17 , the primary 80 MHz is composed of HE Sub-PPDU and thesecondary 80 MHz is composed of EHT Sub-PPDU. This is an example, andeach Sub-PPDU can be composed of several 80 MHz combined. However, itmay be preferable that the primary 80 MHz is composed of HE Sub-PPDUs.Also, the beginning and end of each Sub-PPDU may be the same. Inaddition, each Sub-PPDU may consider preamble puncturing defined in802.11ax and 802.11be. In addition, the L-Length in the L-SIG of the EHTSub-PPDU may be set considering the L-SIG part without considering theprevious part of the L-SIG. That is, as a result, it can be set to theEHT Sub-PPDU length after L-SIG. In addition, the L-SIG of the HESub-PPDU may be configured as defined in HE.

The Pre-Padding field may be configured differently as suggested abovedepending on whether or not SST is applied. Alternatively, it may alwaysbe configured in the same form. For example, if A-PPDU can be supportedonly when SST is applied, the Pre-Padding field can be configured assuggested in 2.2.1. Alternatively, if the A-PPDU can be supportedregardless of whether SST is applied or not, the Pre-Padding field canbe configured as suggested in 2.2.2.

In addition, in all of the above proposals, the A-PPDU can be configuredin such a way that no signal is transmitted in the Pre-Padding field.However, this may be undesirable because an overlapped basic service set(OBSS) STA may determine that a corresponding channel is idle andtransmit a signal.

After pre-padding, no signal may be transmitted for a specific time, andthen the EHT Sub-PPDU including the L-STF may be transmitted. This canhelp Receiver detect L-STF. For example, after pre-padding, no signal istransmitted during the SIFS period (If the Pre-Padding length is a,there is a signal during the Pre-Padding length a and thereafter nosignal during SIFS), and then the EHT Sub-PPDU including the L-STF canbe transmitted (If alpha is considered for Pre-Padding in 2.2.2, aspecific signal can be carried throughout Pre-Padding including alpha,and after that, no signal is transmitted for a specific period (e.g.SIFS), and then L-STF is included. EHT Sub-PPDU may be transmitted).Alternatively, the signal may not be transmitted during the lastspecific time of the entire pre-padding length, and then the EHTSub-PPDU including the L-STF may be transmitted. For example, no signalis transmitted during the last SIFS of the entire pre-padding length (Ifthe Pre-Padding length is a, there is a signal during the first a-SIFSof the Pre-Padding length and no signal during the last SIFS), and thenthe EHT Sub-PPDU including the L-STF can be transmitted.

FIG. 18 is a flowchart illustrating the operation of the transmittingapparatus/device according to the present embodiment.

The example of FIG. 18 may be performed by a transmitting device (APand/or non-AP STA).

Some of each step (or detailed sub-step to be described later) of theexample of FIG. 18 may be skipped/omitted.

In step S100, A transmitting device (transmitting STA) may obtaininformation about a frequency resource and a receiving STA. Informationon frequency resources may include various types of information relatedto the PPDU. For example, information about bands (e.g., informationabout 2.4 GHz, 5 GHz, and 6 GHz bands), information about channels(e.g., 20/40/80/80+80/160/240/320 MHz) and Tone Plan information.

Information about the receiving STA may include the identifier of thereceiving STA, information about the preferred band/channel of thereceiving STA, and the receiving STA's reception capability (e.g.,whether or not EHT-PPDU reception is supported, number of supportedstreams, MCS, etc.).

In step S200, the transmitting device may configure/generate a PPDUbased on the acquired control information. Configuring/creating the PPDUmay include configuring/creating each field of the PPDU. That is, stepS200 includes configuring an L-SIG/RL-SIG/EHT-SIG field includingcontrol information about the PPDU.

As described above, the transmitting device may indicate to the EHT STAthat the transmission PPDU is an EHT MU PPDU and the bandwidth exceeds160 MHz (e.g., 240/320 MHz) using Bit 4, which is a reserved bit of theL-SIG. That is, some bits of the L-SIG may be information about whetherit is an EHT PPDU or another PPDU. Also, some bits of the L-SIG may beinformation about whether the bandwidth of the EHT PPDU exceeds 160 MHz.

Also, the transmitting device may simultaneously transmit the HE PPDUand the EHT PPDU. As described above, the HE-SIG-A field in the HE PPDUmay include information about the bandwidth of the HE PPDU, and HE-SIG-Amay include control information about HE-SIG-B. Also, as describedabove, the HE-SIG-B in the HE PPDU may include control information aboutthe STA to which the HE PPDU is allocated.

In addition, the EHT-SIG-A field in the EHT PPDU may include controlinformation about the bandwidth of the EHT PPDU, and the EHT-SIG-B mayinclude control information about the STA to which the EHT PPDU isallocated as described above.

Also, step S200 may include generating an STF/LTF sequence transmittedthrough a specific RU. The STF/LTF sequence may be generated based on apreset STF generation sequence/LTF generation sequence.

In addition, step S200 may include generating a data field (i.e., MPDU)transmitted through a specific RU.

In step S300, the transmitting device may transmit the PPDU configuredthrough step S200 to the receiving device based on step S300.

While performing step S300, the transmitting device may perform at leastone of operations such as CSD, Spatial Mapping, IDFT/IFFT operation, andGI insertion.

A signal/field/sequence constructed according to the presentspecification may be transmitted in the form of FIG. 10 .

FIG. 19 is a flowchart illustrating the operation of the receivingapparatus/device according to the present embodiment.

The aforementioned PPDU may be received according to the example of FIG.19 .

The example of FIG. 19 may be performed by a receiving apparatus/device(AP and/or non-AP STA).

Some of each step (or detailed sub-step to be described later) of theexample of FIG. 19 may be skipped/omitted.

In step S400, the receiving device (receiving STA) may receive all orpart of the PPDU through step S400. The received signal may be in theform of FIG. 10 .

The sub-step of step S400 may be determined based on the step S300. Thatis, in the step S400, an operation for restoring the results of thephase rotation CSD, spatial mapping, IDFT/IFFT operation, and GI insertoperation applied in step S300 may be performed. In step S500, thereceiving device may perform decoding on all/part of the PPDU. Also, thereceiving device may obtain control information related to a frequencyresource and a receiving STA from the decoded PPDU.

More specifically, the receiving device may decode the L-SIG and EHT-SIGof the PPDU based on the legacy STF/LTF and obtain information includedin the L-SIG and EHT SIG fields.

The receiving STA may acquire/determine the PPDU type or bandwidth basedon the bits included in the L-SIG. In addition, information on thebandwidth/allocated receiving STA for the HE PPDU may beobtained/determined through the HE-SIG-A/B field. In addition, it ispossible to obtain/determine information on the bandwidth/allocatedreceiving STA for the EHT PPDU through the EHT-SIG-A/B field.

In step S600, the receiving device may decode the remaining part of thePPDU based on the information about the PPDU acquired through step S500.For example, the receiving STA may decode the STF/LTF field of the PPDUassigned to it based on the information acquired through S500. Inaddition, the receiving STA may decode the data field of the PPDUallocated to the STA allocated to the receiving STA based on theinformation obtained through S500 and obtain the MPDU included in thedata field.

In addition, the receiving device may perform a processing operation oftransferring the data decoded through step S600 to a higher layer (e.g.,MAC layer). In addition, when generation of a signal is instructed fromthe upper layer to the PHY layer in response to data transmitted to theupper layer, a subsequent operation may be performed.

Hereinafter, the above-described embodiment will be described withreference to FIGS. 1 to 19 .

FIG. 20 is a flowchart illustrating a procedure for transmitting anA-PPDU by a transmitting STA according to this embodiment.

The example of FIG. 20 may be performed in a network environment inwhich a next-generation wireless LAN system (IEEE 802.11be or EHTwireless LAN system) is supported. The next-generation wireless LANsystem is a wireless LAN system improved from the 802.11ax system, andmay support backward compatibility with the 802.11ax system.

The example of FIG. 20 is performed by a transmitting STA, and thetransmitting STA may correspond to an access point (AP). The receivingSTA of FIG. 20 may correspond to an STA supporting an Extremely HighThroughput (EHT) WLAN system.

This embodiment proposes a method for designing a structure of an A-PPDUin which HE PPDU and EHT PPDU are simultaneously transmitted. Inparticular, this embodiment proposes a method of solving the decodingproblem of the HE PPDU and the EHT PPDU by inserting a pre-padding fieldinto the EHT PPDU in the A-PPDU when SST is applied to the EHT STA.

In step S2010, a transmitting station (STA) generates anAggregated-Physical Protocol Data Unit (A-PPDU).

In step S2020, the transmitting STA transmits the A-PPDU to thereceiving STA.

The A-PPDU includes a first PPDU for a primary 80 MHz channel and asecond PPDU for a secondary 80 MHz channel. The first PPDU is a PPDUsupporting a High Efficiency (HE) WLAN system, and the second PPDU is aPPDU supporting an Extremely High Throughput (EHT) WLAN system. That is,the HE PPDU and the EHT PPDU may be aggregated with each other in thefrequency domain and transmitted simultaneously through the A-PPDU.Preferably, the HE PPDU is configured on the primary 80 MHz channel andthe EHT PPDU is configured on the secondary 80 MHz channel.

The first PPDU includes a first Legacy-Short Training Field (L-STF), afirst Legacy-Long Training Field (L-LTF), a first Legacy-Signal (L-SIG),and a first Repeated Legacy-Signal (RL-SIG), a High Efficiency-Signal-A(HE-SIG-A), a HE-SIG-B, a HE-STF, a HE-LTF, and a first data. The secondPPDU includes a pre-padding field, a second L-STF, a second L-LTF, asecond L-SIG, a second RL-SIG, a Universal-Signal (U-SIG), an ExtremelyHigh Throughput-Signal (EHT-SIG), and a second data.

The pre-padding field is configured of a sequence having nocross-correlation with the first L-STF and the first L-LTF. Also, thepre-padding field may be a field formed by repeating a field included inthe first or second PPDU once or several times.

The first PPDU may be configured in order of the first L-STF, the firstL-LTF, the first L-SIG, the first RL-SIG, the HE-SIG-A, the HE-SIG-B,the HE-STF, the HE-LTF, and the first data.

The second PPDU may be configured in order of the pre-padding field, thesecond L-STF, the second L-LTF, the second L-SIG, the second RL-SIG, theU-SIG, the EHT-SIG, the EHT-STF, the EHT-LTF, and the second data.

The receiving STA decodes the second PPDU in the secondary 80 MHzchannel during a Target Wake Time Service Period (TWT SP) when thereceiving STA is an EHT STA to which Subchannel Selective Transmission(SST) is applied. In this case, the receiving STA may obtain informationon the TWT SP after negotiation for the SST. The receiving STA maydecode the second PPDU on a channel allocated during the TWT SP. If thechannel allocated during the TWT SP is the secondary 80 MHz channel, thereceiving STA may access the secondary 80 MHz channel during the TWT SPand use only the corresponding channel. When the SST is applied, thereceiving STA does not need to perform channel switching to decode thesecond PPDU. Accordingly, the length of the pre-padding field when theSST is applied may be shorter than the length of the pre-padding fieldwhen the SST is not applied. This is because it is necessary to securetime for channel switching when the SST is not applied. When thereceiving STA is an EHT STA, the receiving STA may receive or decode thefirst PPDU in the primary MHz channel.

The receiving STA combines and decodes the first L-SIG and the HE-SIG-Aonly in the primary 80 MHz channel when the receiving STA is a HE STAcapable of 160 MHz band (HE STA). This is because no signal for thesecondary 80 MHz channel is detected by the receiving STA due to thepre-padding field. That is, the pre-padding field is a field inserted toprevent errors generated while the HE STA capable of the 160 MHz band(SST may or may not applied) combines and decodes the first L-SIG andthe HE-SIG-A in the entire 160 MHz band. The HE STAs capable of the 160MHz band may also include OBSS 160 MHz capable HE STAs or 160 MHzcapable HE STAs not supported in the BSS.

A length of the pre-padding field may be set from the start of the firstPPDU to the first L-STF or the first L-LTF. The second L-SIG may includeinformation on a length after the second L-SIG in the second PPDU.

The second PPDU may be configured not to transmit any signal for aspecific time period after the pre-padding field. The specific time maybe a time less than Short InterFrame Space (SIFS).

Fields included in the first and second PPDUs do not need to be aligned,but the beginning and end of the first and second PPDUs may be the sameand the lengths of the first and second PPDUs may be the same.

FIG. 21 is a flowchart illustrating a procedure for receiving an A-PPDUby a receiving STA according to this embodiment.

The example of FIG. 21 may be performed in a network environment inwhich a next-generation wireless LAN system (IEEE 802.11be or EHTwireless LAN system) is supported. The next-generation wireless LANsystem is a wireless LAN system improved from the 802.11ax system, andmay support backward compatibility with the 802.11ax system.

The example of FIG. 21 is performed by the receiving STA and maycorrespond to a STA supporting an Extremely High Throughput (EHT) WLANsystem. The transmitting STA of FIG. 21 may correspond to an accesspoint (AP).

This embodiment proposes a method for designing a structure of an A-PPDUin which HE PPDU and EHT PPDU are simultaneously transmitted. Inparticular, this embodiment proposes a method of solving the decodingproblem of the HE PPDU and the EHT PPDU by inserting a pre-padding fieldinto the EHT PPDU in the A-PPDU when SST is applied to the EHT STA.

In step S2110, the receiving station (STA) receives anAggregated-Physical Protocol Data Unit (A-PPDU) from a transmitting STA.

In step S2120, the receiving STA decodes the A-PPDU.

The A-PPDU includes a first PPDU for a primary 80 MHz channel and asecond PPDU for a secondary 80 MHz channel. The first PPDU is a PPDUsupporting a High Efficiency (HE) WLAN system, and the second PPDU is aPPDU supporting an Extremely High Throughput (EHT) WLAN system. That is,the HE PPDU and the EHT PPDU may be aggregated with each other in thefrequency domain and transmitted simultaneously through the A-PPDU.Preferably, the HE PPDU is configured on the primary 80 MHz channel andthe EHT PPDU is configured on the secondary 80 MHz channel.

The first PPDU includes a first Legacy-Short Training Field (L-STF), afirst Legacy-Long Training Field (L-LTF), a first Legacy-Signal (L-SIG),and a first Repeated Legacy-Signal (RL-SIG), a High Efficiency-Signal-A(HE-SIG-A), a HE-SIG-B, a HE-STF, a HE-LTF, and a first data. The secondPPDU includes a pre-padding field, a second L-STF, a second L-LTF, asecond L-SIG, a second RL-SIG, a Universal-Signal (U-SIG), an ExtremelyHigh Throughput-Signal (EHT-SIG), and a second data.

The pre-padding field is configured of a sequence having nocross-correlation with the first L-STF and the first L-LTF. Also, thepre-padding field may be a field formed by repeating a field included inthe first or second PPDU once or several times.

The first PPDU may be configured in order of the first L-STF, the firstL-LTF, the first L-SIG, the first RL-SIG, the HE-SIG-A, the HE-SIG-B,the HE-STF, the HE-LTF, and the first data.

The second PPDU may be configured in order of the pre-padding field, thesecond L-STF, the second L-LTF, the second L-SIG, the second RL-SIG, theU-SIG, the EHT-SIG, the EHT-STF, the EHT-LTF, and the second data.

The receiving STA decodes the second PPDU in the secondary 80 MHzchannel during a Target Wake Time Service Period (TWT SP) when thereceiving STA is an EHT STA to which Subchannel Selective Transmission(SST) is applied. In this case, the receiving STA may obtain informationon the TWT SP after negotiation for the SST. The receiving STA maydecode the second PPDU on a channel allocated during the TWT SP. If thechannel allocated during the TWT SP is the secondary 80 MHz channel, thereceiving STA may access the secondary 80 MHz channel during the TWT SPand use only the corresponding channel. When the SST is applied, thereceiving STA does not need to perform channel switching to decode thesecond PPDU. Accordingly, the length of the pre-padding field when theSST is applied may be shorter than the length of the pre-padding fieldwhen the SST is not applied. This is because it is necessary to securetime for channel switching when the SST is not applied. When thereceiving STA is an EHT STA, the receiving STA may receive or decode thefirst PPDU in the primary 80 MHz channel.

The receiving STA combines and decodes the first L-SIG and the HE-SIG-Aonly in the primary 80 MHz channel when the receiving STA is a HE STAcapable of 160 MHz band (HE STA). This is because no signal for thesecondary 80 MHz channel is detected by the receiving STA due to thepre-padding field. That is, the pre-padding field is a field inserted toprevent errors generated while the HE STA capable of the 160 MHz band(SST may or may not applied) combines and decodes the first L-SIG andthe HE-SIG-A in the entire 160 MHz band. The HE STAs capable of the 160MHz band may also include OBSS 160 MHz capable HE STAs or 160 MHzcapable HE STAs not supported in the BSS.

A length of the pre-padding field may be set from the start of the firstPPDU to the first L-STF or the first L-LTF. The second L-SIG may includeinformation on a length after the second L-SIG in the second PPDU.

The second PPDU may be configured not to transmit any signal for aspecific time period after the pre-padding field. The specific time maybe a time less than Short InterFrame Space (SIFS).

Fields included in the first and second PPDUs do not need to be aligned,but the beginning and end of the first and second PPDUs may be the sameand the lengths of the first and second PPDUs may be the same.

3. Apparatus/Device Configuration

The technical features of the present specification described above maybe applied to various devices and methods. For example, theabove-described technical features of the present specification may beperformed/supported through the apparatus of FIGS. 1 and/or 11 . Forexample, the above-described technical features of the presentspecification may be applied only to a part of FIGS. 1 and/or 11 . Forexample, the technical features of the present specification describedabove are implemented based on the processing chips 114 and 124 of FIG.1 , or implemented based on the processors 111 and 121 and the memories112 and 122 of FIG. 1 , or, may be implemented based on the processor610 and the memory 620 of FIG. 11 For example, the apparatus of thepresent specification may receive an A-PPDU from a transmitting STA; anddecodes the A-PPDU.

The technical features of the present specification may be implementedbased on a CRM (computer readable medium). For example, CRM proposed bythe present specification is at least one computer readable mediumincluding at least one computer readable medium including instructionsbased on being executed by at least one processor.

The CRM may store instruction that perform operations comprisingreceiving an A-PPDU from a transmitting STA; and decoding the A-PPDU.The instructions stored in the CRM of the present specification may beexecuted by at least one processor. At least one processor related toCRM in the present specification may be the processor(s) 111 and/or 121or the processing chip(s) 114 and/or 124 of FIG. 1 , or the processor610 of FIG. 11 . Meanwhile, the CRM of the present specification may bethe memory(s) 112 and/or 122 of FIG. 1 , the memory 620 of FIG. 11 , ora separate external memory/storage medium/disk.

The foregoing technical features of this specification are applicable tovarious applications or business models. For example, the foregoingtechnical features may be applied for wireless communication of a devicesupporting artificial intelligence (AI).

Artificial intelligence refers to a field of study on artificialintelligence or methodologies for creating artificial intelligence, andmachine learning refers to a field of study on methodologies fordefining and solving various issues in the area of artificialintelligence. Machine learning is also defined as an algorithm forimproving the performance of an operation through steady experiences ofthe operation.

An artificial neural network (ANN) is a model used in machine learningand may refer to an overall problem-solving model that includesartificial neurons (nodes) forming a network by combining synapses. Theartificial neural network may be defined by a pattern of connectionbetween neurons of different layers, a learning process of updating amodel parameter, and an activation function generating an output value.

The artificial neural network may include an input layer, an outputlayer, and optionally one or more hidden layers. Each layer includes oneor more neurons, and the artificial neural network may include synapsesthat connect neurons. In the artificial neural network, each neuron mayoutput a function value of an activation function of input signals inputthrough a synapse, weights, and deviations.

A model parameter refers to a parameter determined through learning andincludes a weight of synapse connection and a deviation of a neuron. Ahyper-parameter refers to a parameter to be set before learning in amachine learning algorithm and includes a learning rate, the number ofiterations, a mini-batch size, and an initialization function.

Learning an artificial neural network may be intended to determine amodel parameter for minimizing a loss function. The loss function may beused as an index for determining an optimal model parameter in a processof learning the artificial neural network.

Machine learning may be classified into supervised learning,unsupervised learning, and reinforcement learning.

Supervised learning refers to a method of training an artificial neuralnetwork with a label given for training data, wherein the label mayindicate a correct answer (or result value) that the artificial neuralnetwork needs to infer when the training data is input to the artificialneural network. Unsupervised learning may refer to a method of trainingan artificial neural network without a label given for training data.Reinforcement learning may refer to a training method for training anagent defined in an environment to choose an action or a sequence ofactions to maximize a cumulative reward in each state.

Machine learning implemented with a deep neural network (DNN) includinga plurality of hidden layers among artificial neural networks isreferred to as deep learning, and deep learning is part of machinelearning. Hereinafter, machine learning is construed as including deeplearning.

The foregoing technical features may be applied to wirelesscommunication of a robot.

Robots may refer to machinery that automatically process or operate agiven task with own ability thereof. In particular, a robot having afunction of recognizing an environment and autonomously making ajudgment to perform an operation may be referred to as an intelligentrobot.

Robots may be classified into industrial, medical, household, militaryrobots and the like according uses or fields. A robot may include anactuator or a driver including a motor to perform various physicaloperations, such as moving a robot joint. In addition, a movable robotmay include a wheel, a brake, a propeller, and the like in a driver torun on the ground or fly in the air through the driver.

The foregoing technical features may be applied to a device supportingextended reality.

Extended reality collectively refers to virtual reality (VR), augmentedreality (AR), and mixed reality (MR). VR technology is a computergraphic technology of providing a real-world object and background onlyin a CG image, AR technology is a computer graphic technology ofproviding a virtual CG image on a real object image, and MR technologyis a computer graphic technology of providing virtual objects mixed andcombined with the real world.

MR technology is similar to AR technology in that a real object and avirtual object are displayed together. However, a virtual object is usedas a supplement to a real object in AR technology, whereas a virtualobject and a real object are used as equal statuses in MR technology.

XR technology may be applied to a head-mount display (HMD), a head-updisplay (HUD), a mobile phone, a tablet PC, a laptop computer, a desktopcomputer, a TV, digital signage, and the like. A device to which XRtechnology is applied may be referred to as an XR device.

The claims recited in the present specification may be combined in avariety of ways. For example, the technical features of the methodclaims of the present specification may be combined to be implemented asa device, and the technical features of the device claims of the presentspecification may be combined to be implemented by a method. Inaddition, the technical characteristics of the method claim of thepresent specification and the technical characteristics of the deviceclaim may be combined to be implemented as a device, and the technicalcharacteristics of the method claim of the present specification and thetechnical characteristics of the device claim may be combined to beimplemented by a method.

1. A method in a Wireless Local Area Network (WLAN) system, the methodcomprising: receiving, by a receiving station (STA), anAggregated-Physical Protocol Data Unit (A-PPDU) from a transmitting STA;and decoding, by the receiving STA, the A-PPDU, wherein the A-PPDUincludes a first PPDU for a primary 80 MHz channel and a second PPDU fora secondary 80 MHz channel, wherein the first PPDU includes a firstLegacy-Short Training Field (L-STF), a first Legacy-Long Training Field(L-LTF), a first Legacy-Signal (L-SIG), and a first RepeatedLegacy-Signal (RL-SIG), a High Efficiency-Signal-A (HE-SIG-A), aHE-SIG-B, a HE-STF, a HE-LTF, and a first data, wherein the second PPDUincludes a pre-padding field, a second L-STF, a second L-LTF, a secondL-SIG, a second RL-SIG, a Universal-Signal (U-SIG), an Extremely HighThroughput-Signal (EHT-SIG), and a second data, wherein the pre-paddingfield is configured of a sequence having no cross-correlation with thefirst L-STF and the first L-LTF, wherein the first PPDU is a PPDUsupporting a HE WLAN system, and wherein the second PPDU is a PPDUsupporting an EHT WLAN system.
 2. The method of claim 1, wherein thefirst PPDU further includes a HE-STF, and a HE-LTF, wherein the secondPPDU further includes an EHT-STF, and an EHT-LTF, wherein the first PPDUis configured in order of the first L-STF, the first L-LTF, the firstL-SIG, the first RL-SIG, the HE-SIG-A, the HE-SIG-B, the HE-STF, theHE-LTF, and the first data, wherein the second PPDU is configured inorder of the pre-padding field, the second L-STF, the second L-LTF, thesecond L-SIG, the second RL-SIG, the U-SIG, the EHT-SIG, the EHT-STF,the EHT-LTF, and the second data.
 3. The method of claim 2, furthercomprising: decoding, by the receiving STA, the second PPDU in thesecondary 80 MHz channel during a Target Wake Time Service Period (TWTSP) when the receiving STA is an EHT STA to which Subchannel SelectiveTransmission (SST) is applied.
 4. The method of claim 2, furthercomprising: combining and decoding, by the receiving STA, the firstL-SIG and the HE-SIG-A only in the primary 80 MHz channel when thereceiving STA is a HE STA capable of 160 MHz band (HE STA), wherein nosignal for the secondary 80 MHz channel is detected by the receiving STAdue to the pre-padding field.
 5. The method of claim 3, wherein a lengthof the pre-padding field is set from the start of the first PPDU to thefirst L-STF or the first L-LTF, wherein the second L-SIG includesinformation on a length after the second L-SIG in the second PPDU. 6.The method of claim 1, wherein the second PPDU is configured not totransmit any signal for a specific time period after the pre-paddingfield, wherein the specific time is a time less than Short InterFrameSpace (SIFS).
 7. A receiving station (STA) in a Wireless Local AreaNetwork (WLAN) system, the receiving STA comprising: a memory; atransceiver; and a processor operatively coupled to the memory andtransceiver, wherein processor is configured to: receive anAggregated-Physical Protocol Data Unit (A-PPDU) from a transmitting STA;and decode the A-PPDU, wherein the A-PPDU includes a first PPDU for aprimary 80 MHz channel and a second PPDU for a secondary 80 MHz channel,wherein the first PPDU includes a first Legacy-Short Training Field(L-STF), a first Legacy-Long Training Field (L-LTF), a firstLegacy-Signal (L-SIG), and a first Repeated Legacy-Signal (RL-SIG), aHigh Efficiency-Signal-A (HE-SIG-A), a HE-SIG-B, a HE-STF, a HE-LTF, anda first data, wherein the second PPDU includes a pre-padding field, asecond L-STF, a second L-LTF, a second L-SIG, a second RL-SIG, aUniversal-Signal (U-SIG), an Extremely High Throughput-Signal (EHT-SIG),and a second data, wherein the pre-padding field is configured of asequence having no cross-correlation with the first L-STF and the firstL-LTF, wherein the first PPDU is a PPDU supporting a HE WLAN system, andwherein the second PPDU is a PPDU supporting an EHT WLAN system.
 8. Amethod in a Wireless Local Area Network (WLAN) system, the methodcomprising: generating, by a transmitting station (STA), anAggregated-Physical Protocol Data Unit (A-PPDU); and transmitting, bythe transmitting STA, the A-PPDU to a receiving STA, wherein the A-PPDUincludes a first PPDU for a primary 80 MHz channel and a second PPDU fora secondary 80 MHz channel, wherein the first PPDU includes a firstLegacy-Short Training Field (L-STF), a first Legacy-Long Training Field(L-LTF), a first Legacy-Signal (L-SIG), and a first RepeatedLegacy-Signal (RL-SIG), a High Efficiency-Signal-A (HE-SIG-A), aHE-SIG-B, a HE-STF, a HE-LTF, and a first data, wherein the second PPDUincludes a pre-padding field, a second L-STF, a second L-LTF, a secondL-SIG, a second RL-SIG, a Universal-Signal (U-SIG), an Extremely HighThroughput-Signal (EHT-SIG), and a second data, wherein the pre-paddingfield is configured of a sequence having no cross-correlation with thefirst L-STF and the first L-LTF, wherein the first PPDU is a PPDUsupporting a HE WLAN system, and wherein the second PPDU is a PPDUsupporting an EHT WLAN system.
 9. The method of claim 8, wherein thefirst PPDU further includes a HE-STF, and a HE-LTF, wherein the secondPPDU further includes an EHT-STF, and an EHT-LTF, wherein the first PPDUis configured in order of the first L-STF, the first L-LTF, the firstL-SIG, the first RL-SIG, the HE-SIG-A, the HE-SIG-B, the HE-STF, theHE-LTF, and the first data, wherein the second PPDU is configured inorder of the pre-padding field, the second L-STF, the second L-LTF, thesecond L-SIG, the second RL-SIG, the U-SIG, the EHT-SIG, the EHT-STF,the EHT-LTF, and the second data.
 10. The method of claim 8, wherein alength of the pre-padding field is set from the start of the first PPDUto the first L-STF or the first L-LTF, wherein the second L-SIG includesinformation on a length after the second L-SIG in the second PPDU. 11.The method of claim 8, wherein the second PPDU is configured not totransmit any signal for a specific time period after the pre-paddingfield, wherein the specific time is a time less than Short InterFrameSpace (SIFS). 12-14. (canceled)